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Full text of "Project Sealab report : an experimental 45-day undersea saturation dive at 205 feet / Sealab II project group, edited by D.C. Pauli and G.P. Clapper"

/VAvy 

ONR Report ACR-124 



Project Sealab Report 

An Experimental 

45-Day Undersea Saturation Dive 

at 205 Feet 

t 

Sealab II Project Group 

Edited by 

D. C. Pauli and G. p. Clapper 

Office of Naval Research 



March 8, 1967 






OFFICE OF NAVAL RESEARCH 

DEPARTMENT OF THE NAVY 

Washington, D.C. 



DISTRIBUTION OF THIS DOCUMENT IS UNLIMITED 



FOREWORD 

SEALAB II was the Navy's second major step in a continuing program to 
increase our ability to live and to perform useful work under the sea. Al- 
though the event was well publicized, we have become so accustomed to tech- 
nological advancement that I doubt if many realized the full significance of 
this pioneer effort to support human life and useful activity in the earth's 
most hostile environment. 

SEALAB n involved every phase of engineering includingthe development 
of new materials and techniques, the fabrication of sophisticated equipment 
and the solution to unique physiological and psychological problems. 

It should be a matter of pride to all of us that the Navy was able to pro- 
vide the full spectrum of capabilities necessary to insure the success of such 
an enterprise. 

SEALAB's success puts us at the threshold of an expanding capability 
for military operations on the continental shelf where required. Of equal 
importance to the welfare of the nation, it increased our capabilities in the 
extraction of chemicals and minerals from the sea, the tending of pipelines, 
cables and underwater installations, the culture of marine life for food, and, 
of course, the extension of geophysical exploration and general advancement 
of all earth sciences. 

I am pleased to present this report in accordance with the Navy's policy 
of sharing its information with an interested scientific community. 



^t^-fiAt.ljb 



PAUL H. NITZE 
Secretary of the Navy 



E ^ 





For sale by the Superintendent of Documents, U.S. Government Printing Office 
Washington, D.C. 20402 - Price $2.25 



CONTENTS 

Page 

Foreword i 

Abstract v 

Frontispiece vi 

Chapter 

1 The Man-In-The-Sea Program 1 

2 Objectives of Sealab 11 Project 3 

3 Sealab n Project Organization 11 

4 Major Program Areas 14 

5 The Sealab 11 Surface-Subsurface Complex 26 

6 Project Chronology 30 

7 Conclusions and Recommsndations 32 

SECTION I-EQUIPMENT AND OPERATIONS 

8 Design of the Sealab II Habitat 39 

9 Electrical and Electronic Systems for the Sealab II Habitat 50 

10 Umbilical Cord for the Sealab U Habitat 63 

11 The Design Construction, and Outfitting of Sealab II 67 

12 Modifications and Outfitting of the Sealab II Habitat 87 

13 Sealab II Exterior Lighting 91 

14 Arawak System on Sealab II 94 

15 Handling Characteristics of Sealab 11 97 

16 Sealab 11 Atmosphere Control 110 

17 The Decompression Complex 112 

18 The Support Vessel 121 

19 Site Selection 131 

20 Staging Vessel Mooring Complex 135 

21 Aspects of Communications in Sealab II Project 139 

22 Utilities 147 

23 Operational and Emergency Bills 149 

SECTION II-AQUANAUTS 

24 Aquanaut Biographies 167 

25 Aquanaut Training 177 

26 Aquanaut Daily Routines 182 

27 Future Selection of Aquanauts 187 

SECTION m-MAN-IN-THE-SEA PROGRAMS 

28 Physiological Studies in Sealab II 203 

29 The Telemetering of Human Subjects and Animals Under Water 205 

30 Adaptation to Environmental Stress in Sealab II 214 

31 Determination of Dissolved Gases in Body Fluids 220 

32 Serum Enzyme Study and Hemotological Data 228 

33 Physical Fitness Tests 233 

34 EEG and EKG Observations in Sealab II 237 

35 Neurological, EEG, and Psychophysiological Findings Before 

and After Sealab H 240 



Page 
Chapter 

36 The Sealab II Human Behavior Program 245 

37 Electrically Heated Pressure-Compensated Wet Suits for Sealab II 272 

38 Engineering Evaluation of Sealab n 306 

39 Oceanographic Investigations . 349 

40 The Sealab II Biological Program 366 

41 Sealab II Underwater Weather Station 369 

42 Sealab II Salvage Tests 385 

43 The Benthic Laboratory 394 

44 Ocean-Bottom Mining Technology 402 

45 Utilization of Porpoises in the Man-in-the-Sea Program 407 

46 Dietary Program 412 

47 Mark-VI Mixed-Gas Breathing Apparatus . 417 

48 Carbon Monoxide in the Atmosphere of Sealab 11 423 



ABSTRACT 

Sealab II operations conducted by the Office of Naval Research as a part 
of the man-in-the-sea task of the Deep Submergence Systems Program was 
an interdisciplinary investigation into the usefulness of ocean floor habita- 
tion by the measurement of the ability of man to do useful work while living 
as a saturated diver in equilibrium with the ocean-floor pressure. 

Ocean-floor tasks of the 28 Navy divers and civilian scientists included 
working dives for studying human physiology and performance, experimental 
salvage techniques, biological and physical oceanography, and the evaluation 
of the undersea habitat and associated diving equipment. 

The Sealab II operation was conducted between Aug. 28 to Oct. 14, 1965, 
3000 ft off Scripps Pier at La Jolla, California, in a depth of water of 205 ft. 
Using a synthetic breathing gas of helium, oxygen, and nitrogen, each of the 
three aquanaut teams lived underpressure approximately 1 5 days in an ocean- 
floor habitat, making forays into the 48° F, 5 to 30 ft visibility bottom waters 
for periods ranging from a few minutes to an extended dive of 3 hours. Ex- 
cursion no-decompression dives to 266 ft and 300 ft were accomplished. Div- 
ing from the habitat was accomplished using both semi-closed-circuit breath- 
ing apparatus and hookah (habitat-connected-hose) breathing apparatus. A 
decompression complex new to the Navy consisting of a personnel transfer 
capsule mating with a deck decompression chamber was used for accomplish- 
ing recovery and decompression of aquanauts. 

Sealab II demonstrated that: 

1. The concept of ocean-floor habitation to accomplish a wide range 
of salvage and scientific tasks is compatible with man's ability to 
perform useful work at these depths. 

2. No significant short-time physiological changes occur which re- 
sulted in deterioration of the aquanauts physical condition. 

3. There is a degradation of human performance which increases 
with the complexity of the task being accomplished. 




The U. S. Navy undersea habitat, Sealab II, which housed three ten-man 
aquanaut teams for 15 days each at a depth of 205 ft off the California 
coast at La JoHa from Aug. 28 to Oct. 10, 1965 



VI 



PROJECT SEALAB REPORT 

AN EXPERIMENTAL 

45-DAY UNDERSEA SATURATION DIVE 

AT 205 FEET 

Chapter 1 
THE MAN-IN-THE-SEA PROGRAM 

Sealab II operations had as a backdrop Sealab I, also conducted by the Office of Naval Re- 
search, which had been completed just one year previous to Sealab 11. In Sealab I, four U.S. 
Navy divers had performed an 11-day saturation dive at a depth of 193 ft. 

Prior to Sealab I, extensive saturation pressure -chamber tests had been conducted at 
both the Submarine Medical Center, New London, Connecticut, and at the Experimental Div- 
ing Unit, Washington, D.C. Principal Investigators at these laboratories included CAPT George 
Bond, CAPT Walter Mazzone, and CAPT Robert Workman. The results of these chamber 
tests on test animals as well as human subjects proved that man could be subjected to satu- 
rated diving conditions and successfully decompressed without any ill effects. 

Sealab I operations resulted from an interest generated within the Office of Naval Re- 
search to translate the U.S. Navy's saturated diving capabilities from the diving tank to at-sea 
operations. Sealab I operations were conducted in ideal ocean waters with respect to visibil- 
ity, water temperature, and ocean-floor conditions. 

The habitat used in Project Sealab I was primitive. A large experimental minesweeping 
float nine feet in diameter and 40 ft long was modified with ports and openings and equipped 
with bunks, showers, galley, and gas bottles. This simple habitat was lowered to the ocean 
floor next to Argus Island, an Office of Naval Research ocean research tower, located 30 
miles southwest from Bermuda. 

A standard two-man decompression chamber was used as a submersible decompression 
chamber for Sealab I operations and was handled with the crane installed on Argus Island. 

Handling of the Sealab I habitat in even relatively smooth waters proved to be difficult. 
Many other associated problems were revealed in the Sealab I operation. The project was 
terminated as a result of an impending tropical storm. 

Sealab I did prove to be successful, and for the limited funds available (approximately 
$150,000) did accomplish the end intended— the first step of translating saturated diving from 
pressure chambers to at-sea operations. 

Sealab II was the second step toward this end (Fig. 1). 

However, instead of the clear warm water and hard-bottom conditions of Bermuda, it was 
desired for Sealab II to face the more realistic environmental conditions existing on the con- 
tinental shelf surrounding the United States. The site off Scripps Institution of Oceanography 
at La Jolla, California was selected for these environmental conditions as well as for logistic 
and scientific support considerations. 



MAN-IN-THE-SEA PROGRAM 




Fig. 1. Sealab II on a barge at Long Beach Naval Shipyard shortly 
before it was placed in the water and towed to La JoUa, California 



The Sealab II project, a step in the man-in-the-sea program of DSSP, was initiated in 
January 1965, at which time a goal was set to place the aquanauts on the ocean floor on Aug. 
20, seven months later. Extreme cooperation by all participating Navy, university, and indus- 
trial organizations resulted in coming within eight days of this preset goal. During these 
seven months, the habitat was designed, fabricated, and equipped with specialized atmospheric 
control, communications, and diver's equipments. During this same period, aquanauts were 
selected and trained to respond to the equipments, which were to be their primary life support 
on the ocean floor. The surface-support vessel was modified, and a decompression complex, 
using a new concept, was designed, built, tested, and installed. The fabrication and testing of 
a remote maintainable ocean-floor telemetering station (benthic laboratory) was accomplished, 
as well as the many tasks related to the development of the ocean-floor work programs. Last 
but not least, Tuffy, the porpoise who proved his capability to find and save lost divers, had to 
be trained in the special life saving procedures and integrated into the busy, noisy environment 
surrounding the Sealab II site. 



chapter 2 
OBJEaiVES OF SEALAB II PROJECT 

The major objectives of Project Sealab II were: 

1. Determination of man's general ability to do useful work at a depth of 200 ft in a 
realistic ocean environment under saturated diving conditions. 

2. Determination of physiological changes in man as a result of extended diving. 

3. Measurement of performance to determine work degradation or improvement, as 
compared to surface-diver operations, and as a function of dive time. 

4. Determination of stressful conditions and their effects on the group interactions of 
the aquanauts. 

The degree of success of each of the planned work functions varied considerably because 
of the limited availability of diving time. In general, it can be stated that man's ability to do 
work under saturated diving conditions at a depth of 205 ft was more than amply proved. Actu- 
ally, the diversity of tests, while providing a considerable overall project enhancement, tended 
to limit the measurement of man's capability in each specific field of interest. The determina- 
tion of man's general ability to do useful work at 205 ft in a realistic ocean environment under 
saturated diving conditions implies a wide range of work involvement. Such a diversity of work 
was planned and undertaken in the Sealab Program. The various work assignments were 
as follows: 

All three teams: 

Touch-sensitivity tests 

Arithmetical tests 

Aquasonic intelligibility tests 

Light and form visibility tests 

Stationary target array identification 

Contrast and resolution studies 

Visual acuity tests 

Auditory range studies 

Sound localization studies 

Water clarity meter correlation 

Strength testing 

Triangle assembly tests 

Two-hand coordination tests 

Group assembly tests 

Hookah evaluation 

Time-lapse photography 

Heated wet-suit evaluation 

Plankton studies 

Underwater weather station assembly, Calibration and Inspection 

Fish rake census 

Sediment coring 

Fish cage placement and stocking 

Teams 1 and 2 only: 

Sand movement studies 

Portable EEG, EKG recorder evaluation 



4 OBJECTIVES OF SEALAB II PROJECT 

Teams 2 and 3 only: 

Excursion diving 

Team 1 only: 

Fish migration studies 
Fish gas bladder studies 

Team 2 only: 

Porpoise evaluation 

Team 3 only: 

Foam-in-salvage evaluation 
Salvage tools and equipment evaluation 
Geological airlift evaluation 
Geological corer evaluation 

In addition to the above specifically assigned work assignments, many other assignments 
had to be accomplished as part of the regular routine. These everyday assignments included: 

Watchstanding 
Medical observations 
Housekeeping 
Pressure-pot transfers 
MK-Vl set-up and check 

The investigation of physiological changes in man as a result of the extended saturation 
diving of Sealab II resulted in a conviction that: 

1. No significant short-time physiological changes occur which result in deterioration 
of the aquanauts' physical condition. 

2. Acclimation to stressful temperature changes of Sealab habitat living (85° F) and 
ocean-floor swimming (47° to 54° F) occurs, with the result that aquanauts can perform better 
and for longer periods of time in the surrounding ocean waters. 

The measurement of work performance to determine work degradation or improvement as 
compared to surface-diver operations and as a function of dive duration resulted in the 
following: 

1. The results of a lift-and-pull strength test showed a decrease in exertable strength 
between dry land and Sealab. 

2. The individual triangle assembly (manual dexterity) tests revealed a 37-percent de- 
crease in performance between dry land and Sealab. 

3. The Two-Hand Coordination Test showed a 17-percent decrement in performance 
in Sealab. 

4. The three-dimensional group assembly task took twice as long in Sealab as on 
dry land. 

5. No decrement was found between predive and Sealab mental arithmetic tests. 

Determination of stressful conditions and their effects on the group interactions of the 
aquanauts leads to the conclusion that there can be little doubt that the Sealab environment was 
stressful. The conditions which contributed to this stressful environment included the following: 

1. The water was cold and visibility poor. 

2. The work schedule, requiring long hours of preparation, was very often interrupted, 
delayed or revised. 



OBJECTIVES OF SEALAB II PROJECT 5 

3. Communications were difficult because of helium-speech distortion. 

4. Sleep was often disrupted for most men by the long hours of work, high humidity, poor 
air circulation, and physical complaints of headaches, minor ear infections, and skin rashes. 

However, in spite of the stressful aspects of the situation, the motivation and morale of 
the men were extremely high. Group cohesiveness, as measured by the diver's choices of 
their own team members, increased for each of the three teams from pre- to postexperiment 
measures. Despite a general feeling of accomplishment, many men were dissatisfied with the 
amount of work they personally accomplished. 




Fig. 2. Aquanauts open the Sealab conning tower flood valve 




Fig. 3. Sealab II begins its slow descent to the ocean bottom, 

205 ft below 



OBJECTIVES OF SEALAB II PROJECT 




Fig. 4. Aquanauts Commander M. Scott Carpenter and 
Gunner's Mate First Class Wilbur Eaton prepare to 
enter the water and dive to Sealab II on the bottom 



OBJECTIVES OF SEALAB II PROJECT 




Fig. 5. Commander Carpenter and Eaton enter Sealab 
II through the four -foot entry hatch 



OBJECTIVES OF SEALAB II PROJECT 




Fig. 6. Marine life around the Sealab II conning tower 
shortly after the habitat was occupied by Team 1 



OBJECTIVES OF SEALAB II PROJECT 



i 



Fig. 7. Aquanaut Grigg inspects the Personnel Trans- 
fer Capsule as it sits on the bottom 



10 



OBJECTIVES OF SEALAB II PROJECT 




Fig. 8. Aquanaut Cannon repairs a headset inside Sealab II 



It should be made clear that in spite of all the obstacles and dangers present during 
Sealab n, an unprecedented amount of useful work was accomplished (Figs. 2 through 8). The 
aquanauts' performance of scientific and operational tasks demonstrated clearly that man can 
live in harmony with the hostile undersea environment. Having again demonstrated the tre- 
mendous ability of man to adapt, the future of undersea habitation and exploration should be 
limited only by technology and imagination. 



chapter 3 
SEALAB II PROJECT ORGANIZATION 



INTRODUCTION 



Sealab II, being the multidiscipline operation that it was, was organized on a task- 
assignment basis coordinated through a steering committee. Members of the steering commit- 
tee were selected from the major participating organizations. Steering-committee meetings 
were called at milestone points to review problem areas, delineate task responsibilities, and 
make policy decisions related to safety, schedules, and personnel. 

It has been estimated that the total number of persons who contributed materially to the 
success of Project Sealab II is in excess of 400. To attempt to list all support personnel and 
indicate their contributions to the project would not result in a complete list, and therefore the 
attempt will not be made. However, listed below are the organizations which, through direct 
participation or by furnishing equipment and supporting participants, contributed to the overall 
success of the project. 

MAJOR PARTICIPATING ACTIVITIES 

Atlantic Fleet Mobile Photographic Unit 

Provided documentary photographic coverage of aquanaut training. 

Bureau of Medicine and Surgery 

Approved physiological qualifications of all aquanauts. Set guidelines for surface support 
and saturated excursion diving. 

Bureau of Ships 

Initiated and provided support for salvage programs. Staffed habitat and Decompression 
Complex Certification Board. Provided ARS for surface support. 

Chief of Naval Operations (Op-09) 

Supervised overall still and motion picture documentation. 

Commander Eleventh Naval District 

Provided logistic support and staff personnel during operational phase of the project. 

Experimental Diving Unit 

Tested diving gear and provided 230-ft He-02 decompression tables and technical advice. 

Long Beach Naval Shipyard 

Provided facilities and technical personnel for final checkout and modification of staging 
vessel, decompression complex, and habitat. 

Marine Physical Laboratory 

Designed and constructed benthic laboratory and provided communications equipment 
and support. 

Naval Medical Research Institute 

Initiated and monitored heated wet-suit program. Planned and directed psychological ob- 
servation program during the operational phase. 



11 



12 SEALAB II PROJECT ORGANIZATION 

Naval Operations Support Group, Pacific 

Provided surface diving support and transportation from shore to the support vessel. 

Naval Ordnance Test Station 

Furnished staging vessel and supervisory range personnel. Conducted predive site sur- 
veys, provided supervisory personnel for habitat, decompression complex, and staging vessel 
modification, and provided special equipments and logistic support. 

Naval Electronics Laboratory 

Provided staging area for logistics support and underwater photometric equipments and 
special technical support personnel. 

Office of Naval Research 

Provided overall project management and documentation. Planned and supervised human- 
performance program, decompression complex construction, and public information program. 

Pacific Fleet Mobile Photographic Unit 

Provided documentary coverage of outfitting and operational phases. 

San Francisco Bay Naval Shipyard, Hunters Point Division 

Designed and constructed Sealab II habitat. Provided technical assistance during opera- 
tional phase. Conducted toxicology study of possible habitat contaminants. 

Scripps Institution of Oceanography 

Provided local logistic support, shore facilities, and transportation between shore and 
staging vessel. 

Special Projects Office 

Selected aquanaut teams. Supervised physiological testing. Aided in public information 
activities. 

Submarine Medical Center 

Provided physiological monitoring personnel and equipments. Supervised atmosphere 
control and aquanaut decompression. 

U.S. Naval Research Laboratory 

Supervised gas uptake studies. Analyzed atmosphere purification chemicals and atmos- 
phere samples. Conducted CO2 absorbent efficiency tests. 

U.S. Navy Mine Defense Laboratory 

Provided specifications and design criteria for habitat, surface diving locker, and decom- 
pression complex. Trained aquanauts. Provided technical assistance during operational 
phase. Made engineering evaluation of habitat and diver's equipments. 

ORGANIZATIONS FURNISHING SPECIAL APPARATUS 
AND SUPPORTING PARTICIPANTS 

Battelle Memorial Institute - Underwater power tools and engineering support 

Commander Service Force, U.S. Pacific Fleet - Logistics 

Dixie Manufacturing Company - Decompression complex 

Dunlap and Associates, Inc. - Human performance equipment and test procedures 

EEG Laboratory, Gaustad Sykehus, Norway - Portable EEG, EKG recorder, EEG studies 

Hennessey Productions - Documentary film producer 

International Latex - Experimental wet suits 

Marine Mineral Technology Center - Underwater coring and mining equipment experiments 

Merrett-Chapman-Scott - Operated USNS gear {ARS-7), participated in salvage experiments 

Mine Safety Appliance Company - Salvage tools 

Murphy-Pacific Corporation - Foam-in-salvage equipment and experiment support 

Philadelphia General Hospital - EEG experimental telemetering equipment tests 

Photosonics - Electronic support personnel on staging vessel 



SEALAB II PROJECT ORGANIZATION 



13 



U.S. Naval Applied Science Laboratory - Helium speech unscramblers 

U.S. Naval Hospital, San Diego - Postdive aquanaut physical examinations 

U.S. Naval Missile Center - Porpoise evaluation and audiometric measurements 

of aquanaut s 
U.S. Naval Ordnance Laboratory - swimmer knife evaluation, stud gun engineering 
U.S. Naval Radiological Defense Laboratory - Radio-isotope studies of possible iron 

deficiencies 
U.S. Naval School of Aviation Medicine - Predive aquanaut physical examinations 
U.S. Naval Training Station, San Diego - Provided IBM card coders and observers for 

psychological monitoring 
U.S. Navy Underwater Sound Laboratory - Underwater swimmer auditory test equipment 
U.S. Rubber Company - Experimental heated wet suits 
University of California, Santa Barbara - Environmental stress studies 
University of California Medical School, Berkeley - Blood testing 
Westinghouse Electric - Arawak/hookah gear, staging vessel support personnel 
Yale University - Data collection, psychological studies, computer coding, and data analysis 

The on-site organization is outlined in Fig. 9. It must be emphasized, however, that the 
principal concern of a test of the nature of Sealab II is that of safety of the aquanauts. 



PROJECT DIRECTOR - CAPTAIN L. MELSON 
ALTERNATE PROJECT DIRECTOR - CAPTAIN R. SPENSER 



PROJECT MANAGER -MR. H. O'NEAL 
ASSISTANT PROJECT MANAGER - MR. D. PAULI 



ADMINISTRATIVE 

ASSISTANT 
LT. G. CLAPPER 



DEPUTY FOR PHYSICAL 
SCIENCE AND ENGINEERING 
MR. D. PAULI 
SIO PROGRAM 
SEALAB SHORE CONTROL 
MDL PROGRAM 
WORK PERFORMANCE 



PUBLIC 
INFORMATION 
LT. W. LARSON 



SPECIAL ASSISTANT 
LCDR. M. MACKINNON III 



DEPUTY ON-SITE COMMANDER 
FOR SURFACE SUPPORT 

CDR. T. BLOCKWICK 
DIVING OFFICER 
LOGISTICS 
SUPPORT VESSEL 
SALVAGE EXPERIMENTS 



DEPUTY FOR 
MEDICAL AFFAIRS 
CAPTAIN G. BOND 

SEALAB TOPSIDE CONTROL 

AQUANAUT TEAMS 

PHYSIOLOGY 

AiMUbPHERE CONTROL 



Fig. 9. Sealab II On-Site Organization 



Consequently, to a large extent, the ocean-floor work load of the aquanauts was controlled by 
the Medical Affairs Officer. As this concept of ocean floor habitation moves more toward op- 
erational objectives, the external control of the aquanauts' direct work load will be by a topside 
salvage diving officer. Medical officers will then function in a monitoring and emergency role, 
as they now do in conventional diving operations. 



chapter 4 
MAJOR PROGRAM AREAS 



INTRODUCTION 



Over forty programs were carried out during Project Sealab II. These programs covered 
the following major areas: 

1. Physiology 

2. Human performance 

3. Experimental wet suits 

4. Habitat engineering evaluation 

5. Oceanography 

6. Salvage 

7. Benthic laboratory 

8. Mining technology 

9. Porpoise utilization 

10. Dietetics 

11. Mk-VI semiclosed circuit scuba evaluation 

12. Atmosphere contaminants 

The general concepts and major results of each program are discussed in the following 
sections. 



PHYSIOLOGY 

Previous physiological studies, conducted during Projects Genesis and Sealab I, indicated 
that most physiological parameters monitored would show no significant change under condi- 
tions of high pressure and exotic gas mixtures. Therefore, only those vital functions which 
might assist topside control in medical management of the experiment were monitored. These 
studies included daily blood analysis, inspection of urine and saliva, pulmonary function, elec- 
trocardiographic recordings, body temperature control, exercise tolerance, and routine physi- 
cal tests (Chapter 33). 

By and large, the test results were essentially negative. However, there were suggestive 
trends (Chapter 28) in certain areas which will warrant further intensive investigation. Atten- 
tion was particularly directed to examination of the "stress enzymes," since these indicators, 
together with the corticosteroid determinations, had demonstrated greatest liability during 
past human exposure. As is seen in Chapter 32, these data give provocative evidence of an in- 
creased stress effect on the aquanauts during the first three to five days of undersea exposure, 
with a slow return to normal valucE. It would appear that stress indicators are probably the 
most sensitive physiological warning signals available to topside monitors. This fact will be 
suitably exploited in future undersea programs. 

Physiologically, the most critical area of the project was decompression. Decompression 
schedules may be based on mathematical calculation; however, the validity of such schedules 
can only be established empirically, since there is no simple, accurate method of determining 
inert-gas tension in tissue. 

During Sealab II decompression runs, a test program applying gas chromatography to de- 
termine the dissolved gas levels in urine was conducted (Chapter 31). The results indicate that 
a high correlation exists between the amount of dissolved gas in the urine and the ambient at- 
mospheric concentration. Application of this observation to decompression schedules is under 
serious consideration. 

14 



MAJOR PROGRAM AREAS 



15 



Another major problem encountered in undersea living is that of recording physiological 
parameters while the subjects are outside of their undersea habitat. Several approaches to 
the problem come to mind, two of which were investigated during the experiment. One method 
was the acoustic underwater telemetering of EKG signals from the swimmer to the habitat and 
wire transmission to the surface support vessel (Chapter 29). The second method was the use 
of a miniaturized unit which was carried by the swimmer and recorded EEC and EKG (Chapter 
34). In both programs some expected and unexpected artifacts were encountered. However, 
progress to date shows great promise for the monitoring of vital signs on free swimmers in 
the future (Fig. 10). 




Fig. 10. 



Aquanaut Coffman has electrodes for EKG and 
EEG recorder attached 



Although the complex of environmental stresses present in Sealab II may best be studied 
at the site, considerable insight into the effects of such a stressful situation can be obtained 
by appropriate studies conducted prior to and immediately after the exposure. Nine divers 
were studied before and again after their 15 days in Sealab (Chapter 30). Studies conducted 
included modified maximal work capacity and cold-exposure tests. There is a suggestion, 
based on the data obtained, that some alteration in physiological function may have occurred in 
men living under the conditions present in Sealab II. 



Pre and postdive tests involving neurological, EEG, and psychopsysiological studies were 
also conducted (Chapter 35). The psychophysiological variables included heart rate, respira- 
tion rate, skin resistance, and finger plethysmogram. No significant predive or postdive neuro- 
logical or EEG changes were found, while the only significant difference in psychophysiological 
variables was a drop in arousal level from predive to postdive. 



16 MAJOR PROGRAM AREAS 

HUMAN PERFORMANCE 

The purpose of the human-performance program was to make an overall assessment of 
man's behavior while living in the sea. The program was designed not only to determine how 
well man can perform scientific tasks, but also to study broader aspects of adaptation to life 
and work in the hostile undersea environment. 

Psychomotor tests used during the program were designed to measure the application of 
maximum force (strength test), manipulative dexterity, eye-hand coordination, and the coopera- 
tive assembly by four divers of a three-dimensional configuration. On most of these tests, 
data were obtained on dry land, in shallow water, and during submersion in Sealab. 

The program also included auditory and visual tests. Predive and postdive hearing tests 
were administered to each diver. Data were collected in the water on color and form dis- 
crimination, and the optical properties of light transmission as well as the observation of 
underwater lights. Results were also obtained on the ability of the divers to perform mental- 
arithmetic tests, both before and during the submersion period. 

In addition to the specific tests described above, the men were under continual surveillance 
during submersion by closed-circuit television and open audio channels. The behavior of the 
men was systematically observed and recorded. These data included eating and sleeping hab- 
its, activity levels, variation of mood, morale, motivation, and the general spirit of coopera- 
tion. Following the submersion period, each diver completed questionnaires and medical ex- 
aminations, and was interviewed. 

Results showed that in spite of all the obstacles and dangers present during Sealab 11, an 
unprecedented amount of useful work was done. While some of this work possibly could have 
been performed from the surface, a diver, with his inherent flexibility for on-the-spot decision 
making and planning, was the essential element in the program. Although some degradation of 
work performance occurred, the aquanauts' performance of scientific and operational tasks 
demonstrates clearly that man can live in harmony with the hostile undersea environment. 

EXPERIMENTAL WET SUITS 

The principal objectives of the experimental wet-suit program, as detailed in Chapter 37, 
was to evaluate the concept of supplementing body heat with Joule heating to maintain thermal 
balance during prolonged cold-water exposure. Eight experimental electrically heated 
pressure-compensated wet suits were provided for Sealab II aquanauts (Fig. 11). 

Supplemental heat was generated by resistance wires powered either by a power cable 
terminating in Sealab II or by silver zinc cells worn around the waist. Pressure compensation 
was achieved through use of an open-cell natural rubber latex sponge sandwiched between thin 
layers of solid rubber and injected with gas at depth to maintain normal thickness. 

Evaluations indicate conclusively that adequate thermal control can be realized with this 
approach to protective suits for deep and prolonged cold-water immersion. 

HABITAT ENGINEERING EVALUATION 

The habitat engineering evaluation program (Chapter 38) presents a brief description of 
Sealab H and associated systems and facilities, and their evaluation from an engineering stand- 
point. The evaluation is based on observation, interviews with the aquanauts, and recorded 
data, and includes hull, umbilical cord, baUast system, electrical system, breathing-gas sys- 
tems, gas-sampling system, Arawak system, plumbing and sanitary system, communication 
system, and data-recording system. In general, systems and equipment were satisfactory and 
in most cases performed their designed functions, with a few notable exceptions. These ex- 
ceptions include the food freezer, which would not maintain a sufficiently low temperature, the 
dehumidifiers, which removed water at less than 25 percent of their rated rate, and the CO 2 
scrubber, which was only 60 percent efficient. 



MAJOR PROGRAM AREAS 



17 




Fig. 11. Aquanaut Sonnenburg in Sealab II wearing an ex- 
perimental electrically heated pressure -compensated 
wet suit 



OCEANOGRAPHY 

Programs in physical oceanography and marine biology were conducted by civilian 
oceanographer-aquanauts from the U.S. Naval Mine Defense Laboratory and Scripps Institution 
of Oceanography. 

The Mine Defense Laboratory programs (Chapter 39) were slanted toward physical ocean- 
ography, with emphasis on those aspects which have potential usefulness for application to 
naval problems. Major areas covered included a study of general environmental parameters, 
underwater surveying and mapping, ambient-noise conditions, investigation of the effects of the 
Sealab n environment on plants, bottom-roughness power spectrum, diffusion studies of bottom 
boundary layer and near-bottom turbulence, ultraviolet fluorescence, and wave-induced bottom 
motion (Fig. 12). 

The results of these studies indicate that even though Sealab II was not designed primarily 
as an oceanographic platform, it does provide the capability to attack many significant oceano- 
graphic problems, the solution of which would lead to a better understanding of the marine en- 
vironment and how to exploit it. 

The aim of the Scripps Institution of Oceanography biology program (Chapter 40) was to 
describe the biological activity in, on, and just above the sea floor in the vicinity of the habitat 
and as far away as divers could operate with safety. The program was designed to describe 
the normal bottom fauna and to document any qualitative or quantitative changes that took place 
after Sealab was placed on the bottom. This was done by determining the identities, abun- 
dances, and spatial distributions of the organisms attracted to the Sealab site throughout the 
operation and comparing and contrasting these with the normal sandy-bottom and canyon 



18 MAJOR PROGRAM AREAS 




Fig. 12. Aquanaut Meeks holds on to a rock outcrop- 
ping at the edge of Scripps Canyon, Z66 ft below the 
surface 



faunas, and recording the activities of organisms and their relationships with each other and 
with the physical environment. 

It was possible to carry out an extensive survey of the organisms present around Sealab. 
The data indicate that an object the size of Sealab provided with lights is a very effective fish 
attractant. Observations of predatory and other behavioral interactions, and of patterns of 
distributiwi, have given a preliminary idea of the structure and dynamics of the community of 
animals, particularly fish, attracted to such artificial substrates. 

The oceanographic program conducted by Scripps Institution of Oceanography also included 
an underwater weather station, which was installed and maintained by the aquanauts (Chapter 
41). The weather station provided measurement of current speed and direction, temperature, 
pressure, and ambient light. The data were recorded in Sealab II for diver use and was trans- 
mitted through the benthic laboratory to a shore station where more detailed analysis could 
be performed. 

The data indicate that many phenomena contribute to underwater weather. The identity 
and relative contributions of the many possible sources of energy will require more extensive 
measurement and spectral analysis. Weather at this depth could not be predicted by simple 
manipulation of measured surface parameters, such as waves and tides. 

SALVAGE 

The Supervisor of Salvage, U.S. Navy, sponsored a number of ship-salvage-oriented proj- 
ects in Sealab II (Chapter 42). The general objectives of the several tasks were: 

1. To demonstrate the feasibility of conducting long-term salvage operations mounted 
out of a bottom habitat. 



MAJOR PROGRAM AREAS 19 

2. To determine the capability of divers to accomplish strenuous salvage work during 
prolonged saturation dives. 

3. To perform subjective in situ tests and field evaluation of several new or modified 
tools, systems, and techniques in 205 ft of water. 

4. To determine the feasibility of scuba-equipped divers to use these tools in deep water, 
as compared with hard-hat divers. 

The general objectives were accomplished with considerable success. All assigned tasks 
were performed during Team 3's tenure on the bottom. Diver tasks in general were per- 
formed with dispatch and skill, and consistently in less time than had been programmed (Fig. 
13). It was clearly demonstrated that the saturated diver, as a man, could handle the tools 
employed and accomplish the tasks assigned. This is not, however, to say that the tools in 
each case were optimum. Nor is it to say that all diver-support systems were satisfactory. 
On the contrary, the lack of adequate diver-to-diver and diver-to-topside communications, 
and the inadequate body-heating systems, hampered the divers in the accomplishment of their 
tasks. That they nonetheless were able to perform satisfactorily further emphasizes the feasi- 
bility of scuba-equipped saturated divers, operating from a bottom habitat, performing typical, 
complicated, strenuous salvage tasks. 




Fig. 13. Aquanaut P. Wells injects buoyancy foam into an 
aircraft hull during the Sealab II salvage evaluation 



BENTHIC LABORATORY 



The benthic laboratory (Chapter 43) as used in Sealab II, was an unmanned, remotely op- 
erated electronics complex, housed in an oil-filled inverted dome, or "hive," mounted on the 
sea floor near the Sealab habitat (Fig. 14). This complex was connected through a single co- 
axial cable to the benthic control console one mile away on shore. 



20 



MAJOR PROGRAM AREAS 




Fig. 14. The benthic laboratory is lowered into 
the ocean from the Sealab II surface support vessel 



In addition to control and monitor functions associated with the operation of the benthic 
laboratory, the electronics provides for the multiplex and demultiplex of quite a number of 
television video, audio communication, and digital telemetering channels to and from Sealab 
over the single coax to shore. The ac power required to operate the benthic laboratory is also 
transmitted over the same coaxial cable. 

The bulk of shore-recorded data from Sealab is of questionable value, because conductors 
carrying 3 of 18 bits telemetered ashore were intermittent due to connector failure in the 
Sealab-to-benthic cables. Also, three of the four video coaxial connectors to benthic, along 
with telemetered signals for focus and sensitivity adjustment, were lost during the initial 
benthic -to-Sealab hookup as a result of the cable-connector damage. 

All audio communication channels performed as expected, and no failures occurred in the 
42 days of operation while Sealab was manned. 

MINING TECHNOLCX3Y 

Two methods of mining/sample recovery were evaluated during Project Sealab II (Chapter 
44). These two methods were airlift and the rotary corer. 



In the airlift method, a recovery pipe is suspended from a surface craft to the sea floor. 
Compressed air is injected into the pipe some distance above the bottom, forming an aerated 



MAJOR PROGRAM AREAS 21 

froth in the pipe. The reduction in density in the upper portion of the pipe causes water- 
sediment flow into the bottom. This flow has such velocity that solids are raised to the sur- 
face, where they are discharged into recovery barrels. 

The rotary coring method involves a coring assembly mounted in a frame with tripod legs. 
The device sits on the ocean floor and is intended to drill a six-foot-long core of sand, gravel, 
nodular material, or rock. The unit is lowered and raised from a surface vessel, from which 
power is supplied to a motor mounted on the device. 

Tests of both units indicated promise, but there is still work to do before either become 
operational. With the airlift method, handling is quite difficult because of the long lengths 
(over 200 ft) of large-diameter pipe used. The coring-device unit tipped over each time it 
was placed on the sea floor, indicating a need for adjusting the unit to the topography of the 
area. 

PORPOISE UTILIZATION 

Sealab II provided an opportunity to test the feasibility of using porpoises in conjunction 
with the man-in-the-sea program (Chapter 45). It was planned that Sealab II aquanauts would 
be tethered at all times while swimming at ranges beyond the visual ranges of the habitat. 
However, should a failure occur and the diver become disoriented, a strong possibility exists 
that he would be unable to find his way back to his ocean-floor habitat. Therefore, the avail- 
ability of a trained porpoise to perform certain vital work functions, in particular guiding a 
lost diver back to the habitat, and also carrying equipment and messages to divers working 
some distance from the habitat, would be of great importance. 

It was planned that the porpoise would be summoned from the surface by buzzer to an 
aquanaut at Sealab. That individual would snap a line to one of the rings on the animal's har- 
ness, then turn off his buzzer. The "lost" aquanaut would then summon the porpoise by turn- 
ing on his buzzer. After unsnapping the line that the animal had carried to him, he would have 
a guide back to Sealab (Figs. 15, 16). 

This procedure, using during Sealab, indicated that a porpoise can be trained to perform 
useful and even vital tasks in programs such as Sealab. It can adapt relatively quickly to a 
strange and in many ways disturbing environment, and, once trained, will perform with a high 
degree of precision and reliability. 

An unexpected opportunity developed during this study to observe another seagoing mammal, 
a sea lion that wanderedinto the Sealab area (Figs. 17, 18). The sea lion was trained to respond 
to an underwater buzzer and was observed feeding on the fish that gathered around Sealab. On 
several occasions the sea lion swam into the Sealab entry trunk, breathed the atmosphere, and 
returned to the surface with no ill effects. 

DIETETICS 

In the past, too little importance has been placed on food and food preparation as it may 
affect morale. If man is to be subjected to other than ideal conditions, i.e., living and working 
on the ocean floor for prolonged periods of time, his motivation must not be stinted by being 
underfed. 

In preparation of the menu (Chapter 46), it was necessary to keep in mind the following 
considerations: 

1. All foods must be easily prepared. 

2. Packaging must be compatible with the extreme pressure conditions (at least 110 psia). 

3. Most food would be prepared and eaten on an individual basis, rather than as a group 
of ten men. 



22 



MAJOR PROGRAM AREAS 




Fig. 15. Sealab II aquanauts work with 
Tuffy, the trained porpoise, in a floating 
pen near the Sealab site 



I 



$ 




Fig. 16. Tuffy, wearing a harness, 
swims outside the floating pen 



Comments by the aquanauts indicated that meals were considered palatable and generally 
good, although midway through each of the periods, some of the aquanauts complained about 
the monotony of the meals. 

By general observations via closed-circuit TV, it appeared as though eating became more 
than just a necessity. On the average, though a specific calorie account was not maintained, 
the aquanauts were of the opinion that they had consumed at least one -fourth again as much 
food each day as normal. These opinions were confirmed by observation. 



MK-VI SEMI-CLOSED-CIRCUIT SCUBA EVALUATION 

The initial preparation of gear and the training of Sealab personnel in the use of the Mk-VI 
scuba was accomplished under the supervision of the U.S. Naval Mine Defense Laboratory Div- 
ing Officer. Training encompassed four weeks and included three weeks of diving in the open 
sea at depths ranging from 30 to 180 ft. 



MAJOR PROGRAM AREAS 



23 




Fig. 17. A wild sea lion rests on a buoy 
near the Sealab II surface support vessel 




Fig. U 



A wild sea lion dives near the 
Sealab 11 site 



At the Sealab site, repair and routing maintenance of all diving gear was accomplished in 
the diving locker on the surface -support vessel. Cylinder charging for Teams 1 and 2 was ac- 
complished in the diving locker, but Team 3 employed a charging line from topside to the in- 
side of the habitat, allowing the empty cylinders to be charged on the bottom. 



24 



MAJOR PROGRAM AREAS 



In general, for deep-excursion diving to 300 ft the Mk-VI was considered outstanding. All 
aquanauts agreed that the Mk-VI was superior to the open-circuit scuba. The men liked the 
Arawak, but preferred free diving with the Mk-VI. 

With the Mk-VI, using 85 percent He, 15 percent Oj, gas-supply duration was, in many 
cases, lower than the expected 70 minutes at 205 ft. 

ATMOSPHERE CONTAMINANTS 

Prior to Sealab II it was expected that some contaminants would be present in the atmo- 
sphere. It was thought that the major problems would be presented by hydrocarbons, the ma- 
jority of which would be produced by cooking. To combat this possibility, any type of frying 
was prohibited, and a 50-pound charcoal filter was installed in the Sealab air-conditioning sys- 
tem to remove hydrocarbons. Although there was some hydrocarbon buildup, the charcoal 
proved to be effective and hydrocarbons were no problem. 

During the latter part of the operation, however, the aquanauts frequently complained of 
headaches (Chapter 48). The presence of carbon monoxide in the atmosphere was suspected 
as the possible cause, and tests were carried out for its detection. Values of approximately 
20 ppm CO were reported. 

In an attempt to remove the CO from the atmosphere, four of the lithium hydroxide canis- 
ters in the CO, removal system were partially filled with Hopcalite, a catalyst used aboard 
nuclear submarines for the oxidation of CO. 

Later it was surprising to find that the CO concentration in Sealab had been decreasing 
for several days prior to placing Hopcalite in the system. Also, there was no noticeable 




Fig. 19. Aquanaut Tolbert uses a special plant nutrient 
for plants grown in Sealab II 



MAJOR PROGRAM AREAS 25 

change in the slope of the curve after the Hopcalite was in place. This observation raises 
doubts as to whether the Hopcalite was at all effective. Possibly, CO was generated through 
some process which was stopped when CO was suspected of being a problem. After this, the 
CO was removed gradually by some still unknown mechanism. 

The Sealab II environmental study included an attempt to grow barley and marigold plants 
from seeds in the Sealab atmosphere (Fig. 19). The barley seedlings did well, and were 
healthy, but the marigold seeds produced only one sprout. Control plants were grown at 
Texas A & M College. 



Chapter 5 
THE SEALAB II SURFACE-SUBSURFACE COMPLEX 



INTRODUCTION 



While most of the machinery and equipment used in Sealab II were off-the-shelf items, 
there were four major pieces of equipage which were unique to the project and were not di- 
rectly associated with the programs of the preceding section. These four were: 

1. Sealab n habitat 

2. Personnel Transfer Capsule (PTC) 

3. Deck Decompression Chamber (DDC) 

4. Surface support vessel 

These four, with their installed machinery as discussed below, comprised the Sealab n 
complex. 

SEALAB II HABITAT 

The Sealab II habitat (Chapters 8, 11, and 12) is a nonpropelled, seagoing craft which can 
be lowered into the ocean and emplaced on the ocean floor. It served as an underwater habitat 
wherein ten aquanauts lived for periods of 15 to 30 days in an artificial atmosphere. 

When on the ocean bottom, Sealab II's living compartment was at a pressure equal to am- 
bient pressure. In effect, the aquanauts lived in an "air" bubble contained beneath a dome. 
The boundaries of the compartment were subjected only to the differential pressure between 
the "air" and the water outside. Therefore, although the habitat was designed as a pressure 
vessel so that it could be pressurized on the surface, the living compartment was not subjected 
to total bottom pressure when it was emplaced. 

The living compartment is a cylinder 12 ft in diameter and 57 ft long, designed for an in- 
ternal working pressure of 125 psi, in accordance with the ASME Unfired Pressure Vessel 
Code. When the habitat was submerged, access was gained through an antishark cage suspended 
below a four-foot-diameter hatch in the bottom of the hull. 

The living compartment was divided into four areas, the aftermost of which was the entry 
way, into which the access hatch opened. This entry way contained showers and stowage space 
for diving gear. 

Just forward of and separated from the entry way by a waterproof dutch door was the labo- 
ratory area. The laboratory area contained a built-in sink and cabinets, a 50-gallon water 
heater, a 150-gallon emergency fresh-water tank, the breathing-gas control panel (Fig. 20), 
and the communication station with its associated equipment. 

Forward of the laboratory area was the galley area, which contained a built-in sink and 
cabinets, electric cook top, chill box, freezer, electrical power transformers, and the major 
components of the habitat air-conditioning system (Fig. 21). 

The forwardmost space was the berthing area. It contained bunks for the ten aquanauts, 
storage lockers, a large drop-leaf table, and at the forward end, a 30-in. emergency escape 
hatch. A total of eleven 24-in. viewing ports were provided throughout the four spaces. 



26 



SURFACE-SUBSURFACE COMPLEX 



27 




Fig. 20. Aquanaut Carpenter checks the breathing-gas control panel 



In the three forward spaces, the overhead was insulated with one-inch cork, the sidewalls 
with two-inch cork, and the deck was made of solid concrete, which was part of the fixed bal- 
last. The overhead of the living spaces was fitted with three ballast tanks, which were used 
as variable ballast during raising and lowering operations. 

The atmosphere in the living compartment contained approximately 85 percent helium, 
11 percent nitrogen and 4 percent oxygen, at approximately 103 psia. The gas in the atmo- 
sphere was replinshed from spare bottles of helium and oxygen outside the hull. Also, replen- 
ishment gas was available via the umbilical from the surface -support vessel. The umbilical 
also contained a communication cable, a gas-sampling hose, a compressed-air hose, and an 
alternate electrical power cable, while primary electrical power and fresh water were supplied 
via power cable and vinyl pipe from shore. 



THE DECOMPRESSION COMPLEX 



The at-sea decompression of ten divers saturated at a depth of approximately 200 ft pre- 
sented a new problem for the U.S. Navy (Chapter 17). First, the men would have to be lifted 
from the ocean floor in a personnel transfer capsule (PTC), maintaining the ocean-floor pres- 
sure, to the surface-support vessel; second, they must be transferred to a larger, more com- 
fortable deck decompression chamber (DDC), where they undergo a lengthy decompression. 

The PTC is basically a cylinder 10 ft long and 6 ft in diameter, with a 27-in. entrance hatch 
on one end. The cylindrical portion sits on a removable stand which provides five feet of clear- 
ance for gaining entrance through the hatch. Ballast to provide negative buoyancy is incorpo- 
rated into the base of the stand and in a lower ballast tray clamped to the stand base. The 
lower tray can be released from the stand to serve as an anchor in the event that aquanauts in 
the PTC must make a controlled ascent to the surface, using an escapement mechanism in the 
stand, rather than being lifted aboard the surface-support vessel by crane. 



28 



SURFACE -SUBSURFACE COMPLEX 




Fig. 21. Aquanaut Sonne nburg replaces lithiura 
hydroxide canisters in the Sealab II air condi- 
tioning system. The canisters remove carbon 
dioxide from the atmosphere. 



An emergency, 24-hour life-support system, providing breathing gas and CO2 removal was 
self-contained. However, normal operation included an umbilical from the surface- support 
vessel which provided breathing gas, a communication link, and power for CO2 removal. 

The DDC is another cylindrical structure 23 ft long and 10 ft in diameter. It contains 
berthing for ten men, an entrance lock, a medical lock, a CO 2 scrubber, a mating hatch for the 
PTC, and an exhaust manifold with constant-flow regulators. 

In normal operations, with the PTC on the ocean floor, the saturated divers enter and 
close the hatch, sealing themselves at bottom pressure. The PTC is then hoisted aboard the 
support vessel, where the capsule is removed from the stand and base and placed on the mat- 
ing hatch of the DDC. After the mated hatches are sealed, the pressures in the PTC and DDC 
are equalized and the divers enter the DDC from the PTC. The DDC and PTC hatches are then 
closed and the divers start decompression as the PTC is returned to the ocean floor to serve 
as the emergency capsule for the next team. 

SURFACE -SUPPORT VESSEL 



The support vessel (Chapter 18) as configured for the project is made from two 110 x 34 ft 
YC barges spaced 22 ft apart and connected at one end by a covered structure. This structure 



SURFACE-SUBSURFACE COMPLEX 29 

provides a rigid platform with overall dimensions of 110 x 90 ft with a 65 x 22 ft open well at 
one end. The port barge contains an open bay, a portion of which is roofed over and used as a 
divers' ready room. The DDC was installed in the remainder of the bay. Principal items of 
machinery included on the support vessel were three ac generators with a total capacity of 
460 kw, two 15,000-pound-pull winches, a high-pressure air compressor, a low pressure air 
compressor, and a 100-ton lima crane, restricted to a 50-ton working load as mounted. 

On the starboard barge, 01 level, two vans with a connecting enclosure were installed for 
use as the Sealab control center. Included in the vans were communications, atmosphere con- 
trol, and medical monitoring equipment. Other installations included a counterweighted sys- 
tem for lowering and raising the PTC and Sealab and a breathing-gas storage and distribution 
system. 

With the aquanauts in the habitat, it was necessary that motion of the support vessel be 
limited so that any given point would remain within a ten-foot circle. This was accomplished 
with a five-point moor. Tension in four of the five legs was measured and recorded continu- 
ously. These data proved to be invaluable in maintaining position without undue strain in any 
mooring leg. 



Chapter 6 
PROJECT CHRONOLOGY 

The first official Sealab II planning meeting was held on Jan. 21 and 22, 1965. At this 
meeting, for planning purposes, it was decided that a schedule would be adopted which would 
result in Sealab 11 being placed on the bottom at La JoUa on August 15, 1965. Although numer- 
ous problems plagued scheduling, the following chronology shows that the original schedule 
slipped only eleven days throughout the seven months of preparation for the project. 

Jan. 13, 1965 - Scripps Canyon selected as the general site for Sealab II. 

Jan. 21-22 - First Sealab II planning meeting held at the U.S. Naval Mine Defense 
Laboratory 

Feb. 3 - Sealab II Steering Committee established: 

Mr. H. A. O'Neal, Chairman ONR 

CAPT L. B. Melson ONR 

CAPT G. F. Bond SPO 

Mr. S. Hersh SPO 

Mr. T. Odum MDL 

Mr. H. Talkington NOTS 

LCDR M. MacKinnon SFBNSY(HP) 

Dr. V. Anderson MPL 

Dr. E. W. Fager SCIO 

Feb. 10 - Specifications for decompression complex given to bidders. 

Feb. 26 - Anchor pull tests conducted at site. 

Mar. 1 - TV site survey made with YFU-53 

Dixie Manufacturing Company of Baltimore selected to fabricate the 

decompression complex. 
Fabrication of Sealab habitat underway at SFBNSY(HP). 

Apr. 1 - First twelve-foot-diameter dished head for Sealab habitat formed by explo- 

sive methods at SFBNSY(HP). 

Apr. 27-28 - Sealab II Steering Committee meeting at SCIO. 

May 4-5 - Additional TV site surveys made. 

July 1 - Fabrication of Sealab habitat completed at SFBNSY(HP). 

July 5 - Sealab II habitat arrives at LBNSY by barge. 

Aquanauts arrive at LBNSY. 

July 7 - Structural Certification Board is briefed on Sealab II construction 

at SFBNSY(HP). 

July 8 - Structural Certification Board inspects Sealab II habitat at LBNSY. 

July 13-16 - Five-point support vessel moor laid by USNS GEAR at site. 



30 



July 


15 


July 


23 


July 


29 


Aug. 


4 


Aug. 


8 


Aug. 


17 


Aug. 


21 


Aug. 


23 


Aug. 


26 


Aug. 


28 


Aug. 


31 


Sept. 


12 


Sept. 


14 


Sept. 


26 



Sept 


. 28 


Oct. 


1 


Oct. 


5 


Oct. 


10 


Oct. 


11 


Oct. 


12 


Oct. 


13 



PROJECT CHRONOLOGY 31 

Structural Certification Board inspects decompression complex at Dixie 
Manufacturing Co. 

Sealab II christened at LBNSY 

PTC completed at Dixie and shipped via truck to LBNSY. 

DDC completed at Dixie and shipped via rail to LBNSY. 

PTC arrives at LBNSY. 

DDC arrives at LBNSY. 

Completed Sealab II trim tests at LBNSY. 

Sealab II arrives at La Jolla site. 

Sealab II and decompression complex certified for use. 

Sealab II placed on bottom at 205 ft. 

Team 1 enters Sealab. 

CDR M. Scott Carpenter in Sealab 11 speaks with astronaut Gordon Cooper 
in GT-5. 

Benthic laboratory placed on bottom near Sealab. 

Team 1 comes to surface for decompression in DDC. 
Team 2 enters Sealab 11. 

Team 1 completes decompression. 

Team 2 comes to surface for decompression in DDC. 
Team 3 enters Sealab 11. 

President L. B. Johnson talks by phone with CDR M. Scott Carpenter who 
is in the DDC undergoing decompression. 

Team 2 completes decompression. 

Aquanauts Sheats and Grigg in Sealab 11 talk by phone to Oceanauts Lebon 
and Cousteau in Conshelf HI in Mediterranean Sea. 

First excursion dives made from Sealab II to 300 ft. 

Team 3 brought to surface to end operations. 

Sealab II raised to the surface. 

Team 3 completes decompression. 

Sealab n towed back to LBNSY and lifted out of water. 



Chapter 7 
CONCLUSIONS AND RECOMMENDATIONS 

Sealab n Steering Committee 

INTRODUCTION 

On December 9, 1965, the Sealab n Steering Committee met as a group for the last time 
to formulate conclusions and recommendations for Project Sealab 11. The results of this meet- 
ing follow. 

MAJOR MAN-IN-THE-SEA CONCLUSIONS 

1. Reasonably large groups of men can live for protracted periods (15 to 30 days) at 205 ft, 
have a large degree of autonomy, accomplish useful work, be safely decompressed, and show 
no apparent serious adverse physiological or psychological effects. 

2. The U.S. Navy's first experience with no-decompression excursion dives from a start- 
ing depth of 205 ft in a saturated state to a depth of 266 and 300 ft was successful. This experi- 
ment represents an important addition to undersea diving technology. 

3. There is a clear degree of diver adaptation to cold water, as shown both by interviews 
with the aquanauts and by predive and postdive cold-water-immersion physiological 
measurements. 

4. Adequate protection against cold water can be obtained for extended periods by the 
use of heated suits. Swimmers without supplementally heated suits are limited to less than 
one hour of useful work in 47° to 54° F waters. 

5. A degradation of work capability varying between 17 and 37 percent, as compared to 
the warm, shallow-water capability, occurs as a result of the many adverse factors encoun- 
tered in the Sealab environment. 

6. Improved tools and techniques for the ocean environment show promise for the accom- 
plishment of salvage tasks and other undersea work functions. 

7. Based on the analysis of the overall performance of the aquanauts, criteria can be de- 
veloped to assist in the selection of future aquanauts. 

8. The interaction between man and porpoise has shown that to depths of 200 ft, the por- 
poise can be extremely useful to man-in-the-sea operations. 

9. In situ living offers a new and important methodology to scientific, biological, geo- 
logical, ocean-floor investigations. 

10. Although vastly improved over Sealab I, the habitat and much of the diving equipments 
are still rudimentary and not yet suited for routine operations. 

11. Present state-of-the-art deep-water swimmer communications and ocean-floor navi- 
gation systems are unacceptable for future man-in-the-sea operations. 



32 



CONCLUSIONS AND RECOMMENDATIONS 33 

12. A completely autonomous habitat is not possible without a reliable underwater power 
package and complete, integrated life-support system. 

13. Explosive forming of 12-ft-diameter dished heads from one-inch mild steel is 
feasible. 

14. Counterweight lowering systems provide a greatly improved technique for lowering 
large objects where inertia! and lowering-vessel motions axe critical. 

15. Offshore telemetry stations using remote manipulators for accomplishing component 
replacement are practical and have considerable merit. 

COMMENTS AND RECOMMENDATIONS 

In general, the Sealab n complex and operations were highly satisfactory. Fast response 
obtained from the entire U.S. Navy diving community, a number of Navy laboratories and 
Shipyards, and several selected contractors made possible the project initiation and prepara- 
tion for field operations within the short, available time span of seven months. A critique of 
deficiencies of the Sealab n complex yields the following recommendations. These recom- 
mendations should be considered in modifying the complex for future undersea experiments. 
However, they should not be considered as all-encompassing for enabling deeper operations 
or operations in unprotected areas. 

HABITAT 

1. A leveling technique and reliable local and remote level- measuring equipment must 
be provided in future sea habitats. 

2. Noise generation should be reduced to a minimum for both comfort and increased 
communications intelligibility. Both sound and light surveys are recommended. 

3. A special oceanograph viewing port should be provided giving an increased angle of 
observation. The feasibility of bubble-type observation ports should be investigated. 

4. More space should be allowed for storage, maintenance, and setup of diving gear. 
Maximum use of space should be made for storage cabinets for general storage and for scien- 
tific sample storage. 

5. Improved environmental control is needed. Research should be undertaken to deter- 
mine the comfort zone for humans in Sealab-type atmospheres. 

6. The ballast, flood, and blow system should be re-evaluated. At deeper depths, remote 
control of valving is a necessity. 

7. A re-evaluation of the entire habitat inside arrangement from the human-engineering 
aspect is desirable. 

8. The arrangement of the habitat communications center should be improved. 

9. Photographic conditions should be improved by installing special photographic lights. 

10. The method of sealing internal port covers should be modified. 

11. Outer port covers should be hinged. 

12. All inside surfaces should be insulated to prevent condensate drippage. 

13. The exit area must be rearranged to provide more space for dressing, etc. 



34 CONCLUSIONS AND RECOMMENDATIONS 

14. Because of the difficulty of entry while wearing flippers, other entry techniques need 
investigations, i.e., an elevator. 

15. The bathtubs in the entry should be either improved (insulated) or removed, as they 
were not used as presently configured. 

16. Investigate the possibility of providing a dry room under the entry trunk to alleviate 
space problems. 

17. A large port is needed so that swimmers can be observed outside near the critical 
entrance area. 

18. Particularly near the entrance area, eliminate as many cables as possible that may 
cause diver entanglement. 

19. If necessary, bottom stabilization should be achieved in the area adjacent to the 
entrance. 

20. Storage racks, hooks, etc. should be provided in the shark cage area for external 
wet-storage. 

21. The lighting in and around the shark cage should be improved. 

22. Rearrangement and auxiliary handling gear must be provided so that men do not have 
to don diving gear to place supplies in or remove supplies from the dumbwaiter. 

23. A method of supply that does not block the entry way should be devised. 

HANDLING PROCEDURES 

1. Facilities must be available for a gas-fill capability and pressure test to lowering 
pressure on site. 

2. Sufficient flexibility in ballasting should be provided to permit changes in raising and 
lowering procedures and to control trim and level without subjecting the habitat to unstable 
conditions. 

3. The ballasting system should provide the capability of overpressurizing the habitat on 
the bottom to insure adequate port and hatch seals prior to raising. 

4. Flexibility and reliability during handling operations could be improved by obtaining 

a. A cable footage counter 

b. The weights, in air and water, of all equipment to be handled 

c. A dynamometer capable of weighing loads up to 20 tons. 

DECOMPRESSION COMPLEX 

1. To provide the capability of handling and mating in higher sea states, different handling 
and mating appurtenances must be provided. 

2. The following improvements to the DDC are recommended: 

a. Bunks (at least seating) in the outer lock 

b. Improvement of temperature and humidity control 

c. Provision of charcoal scrubber 

d. Automatic decompression gas controls 

e. Better matching counterbalance spring on top hatch 

f . Future chambers for this purpose should have at least three locks to provide for 
emergency medical purposes. Gas control of each lock should be independent. 



CONCLUSIONS AND RECOMMENDATIONS 35 

3. Internal gas controls on the PTC, not used extensively during the operation, need rede- 
sign and a better gas -analysis system provided. 

4. A method should be found to keep fish, attracted by the lighting, from collecting in the 
PTC. The light is necessary for swimmer guidance. 

5. An emergency CO 2 scrubbing technique should be provided for the PTC. The hand- 
operated scrubber has not been fully evaluated. 

TRAINING 

1. A continuous aquanaut training program should be established to maintain the excellent 
level of training attained for Sealab H. The program should include a minimum number of 
He/Oj dives on a monthly basis. 

2. Mk-VI training classes should be limited to a maximum of 14 people. A four-week 
course should be adequate for an experienced diver . 

3. Aquanauts should be trained in the same groups that wiU be living together on the 
bottom. 

DIVING PROCEDURES AND EQUIPMENT 

1. Safety precautions as outlined in the Diving Manual must be strictly adhered to. 

2. The adaptation of the Mk-VI for Sealab-type operations is a necessity. Areas of study 
should include: 

a. Elimination of nonmagnetic requirements. However, substituted parts should be 
designed so as to be noninterchangeable with nonmagnetic gear parts. 

b. Revision of the Mk-VI manual. 

c. Quality control to obtain proper part interchangeability. 

d. Relocation and modification of critical control components to prevent snagging. 

e. Compatibility for SPU operations. 

f. Buddy breathing capability. 

3. Insure that all necessary diving equipment spare parts are in hand several months 
before the scheduled start of training and operations. 

4. The noise of the Arawak compressors needs suppression. 

5. Investigate the incorporation of a self-tending reel, quick-release capability, and 
"come home" bottles in future Arawak-system design. 

6. Arawak hoses should be slightly negatively buoyant. 

7. Investigate improvements in the heated suit design to provide greater reliability and 
improved battery configuration. 

8. Positive steps must be taken to prevent pressure-compensated suit buoyancy problems 
from occurring which result in threat to life. 

9. The PPI Pump Manual needs revision. 

10. Vehicles for saturated swimmers must be investigated. 

11. Diver lights need re-evaluation in terms of available light sources. 



36 CONCLUSIONS AND RECOMMENDATIONS 

12. Investigate the development of new diver pressure gages for the deeper depths ex- 
pected in the future. Keep in mind the necessity for fail-safe operation when divers are work- 
ing above their saturation depth. 

13. Provide snap hooks for carrying tools and other gear on the diver's belt. 

14. Improve the method of coding bottom boundary and tether lines. 

COMMUNICATIONS AND INSTRUMENTATION 

1. Reliable communications must be developed for swimmer to swimmer, swimmer to 
habitat, and swimmer to staging vessel. 

2. Reduction of ambient bacl^round noise will improve communications using existing 
communications equipment. 

3. Direct communications should be available between the Sealab diving station and the 
staging-vessel diving platform. 

4. Provide high-resolution vidicon tubes for accurate TV monitoring of aquanaut activity. 

5. Investigate improved methods of sealing habitat TV cameras against penetration by 
the helium atmosphere. 

6. At least three stations in the habitat should be monitored by TV continuously. These 
are the gas station, watch station, and entrance area. 

7. Investigate methods of protecting TV tubes against damage by direct light flashes, i.e., 
photographic flash bulbs. Heat-absorbent glass with absorption characteristics matched to the 
flash-bulb intensity characteristics should solve this problem. 

8. An Integrated oceanographic suit of instrumentation should be incorporated in future 
Sealabs employed for oceanographic purposes. 

9. Oceanographic instrumentation read-out should be internal, with external data storage. 



Section I 
EQUIPMENT AND OPERATIONS 



chapter 8 
DESIGN OF THE SEALAB II HABITAT 



W. B. Culpepper 

U. S. Navy Mine Defense Laboratory 
Panama City, Florida 



INTRODUCTION 

The Sealab II habitat served as an undersea habitat (250 ft maximum depth) for 28 aqua- 
nauts for a period of 45 days (Fig. 22, 23). As such, it was equipped with the necessary life- 
support equipment such as breathing- gas systems, air-conditioning systems, berthing, food- 
stowage and preparation facilities, sanitary facilities, work space, and communication, and 
electrical power, and lighting systems. It is capable of maintaining a positive buoyancy ade- 
quate for surface tow. Water ballast is used to provide necessary negative buoyancy for low- 
ering and to increase negative buoyancy for stability once it is placed on the sea bottom. 




Fig. 22. The kitchen and laboratory areas in the Sealab II habitat 



HULL 

General 

The hull for the Sealab II habitat was designed and fabricated in general accordance with 
Fig. 24. It is 12 ft O J3., and 57 ft long with a semi-elliptic head at either end. The hull was 
designed and fabricated in accordance with the ASME boiler code for unfired pressure vessels 
and is capable of withstanding an internal working pressure of 125 psig. 

39 



40 



DESIGN OF THE SEALAB II HABITAT 




Fig. Z3. The berthing area of the Sealab II habitat 



Viewing Ports 

The hull is provided with eleven viewing ports. These ports are approximately two feet in 
diameter and capable of withstanding the internal design pressure of 125 psig. 

Access Openings 

The hull is provided with three access openings. The bottom entry hatch is approximately 
four feet in diameter and located in the hull bottom in the entryway. The emergency escape 
hatch is approximately 27 in. in diameter and located in the hull bottom near the bow. The 
surface access hatch is approximately 27 in. in diameter and located in the top of the hull 
amidship. 

Entry Trunk 

The entry trunk is eight feet by eight feet and extends two and one-half feet below the hull 
bottom. This trunk provides a displacement volume to compensate for the expected bottom- 
pressure variations due to tidal action in addition to normal internal pressure changes. 



Shark Cage 

The shark cage is eight feet wide by 12 ft long, and extends from the entry trunk down to a 
point one foot above the Sealab II support base. A one-foot-high flexible extension is attached 
around the bottom of the shark cage. This allows conformity with an uneven sea bottom. 



DESIGN OF THE SEALAB II HABITAT 



41 




M 
C 
n) 
^^ 

u 

u 
o 



. — I 



oo 



42 DESIGN OF THE SEALAB II HABITAT 

Hull Penetrations 

Hull penetrations for all gas lines, water lines, and sanitary drains are located as low on 
the hull as possible to minimize flooding or atmosphere loss in the event a line may carry 
away. All penetrations are optimally located so as to minimize length of pipe runs in Sealab n, 
in particular, high-pressure gas lines. All penetrations are either double- stuff ing tube type 
or piping direct welded to the hull. A wiring trunk is provided for the benthic lab equipment 
and outside divers' lights. This trunk is approximately 10 in. I. D. and extends from the hori- 
zontal centerline of the hull to a point approximately two and one- half feet below the hull bot- 
tom. A smaller three- inch IPS* trunk is installed concentrically inside the larger trunk to 
provide for electrical shielding of the divers' lights power cables. The wiring trunk is fitted 
with a pressure-tight cover which may be easily removed for installation of required cables 
(see Chapter 9). 

Bilge Drains 

Bilge drains fore and aft are provided for draining bilges to sea while on bottom. These 
drains are provided with valves for manual operation. 

Ballast Tanks 

The Sealab II is provided with three internal ballast tanks and one external ballast tank. 
The three internal ballast tanks are arranged fore and aft and shall contain the full length, up- 
per portion of the hull volume to a maximum depth of three feet. These tanks are designed to 
withstand a 15-psi minimum pressure differential across the flat bottoms. Each tank is fitted 
with two vent valves, one at either end, and one flood valve. Limber holes are provided in the 
internal structure of the tanks to insure complete venting. 

The external ballast tank is approximately eight feet in diameter by seven feet high and 
located amidship on top of the hull so as to provide a breakwater around the upper access hatch 
while the craft is on surface. This tank is fitted with one vent valve and one flood valve and is 
designed to withstand a 15-psi minimum pressure differential. This tank is also fitted with an 
access hatch in the top to provide surface access to the Sealab 11 interior. 

Ballast System 

A water ballasting system is designed to provide the following characteristics: 

a. Surface Tow 26 tons positive buoyancy 

b. Surface (Prior to lowering) 7 tons positive buoyancy 

c. Lowering (Raising) 4 tons negative buoyancy 

d. On bottom 12 tons negative buoyancy 

This system is designed for surface operation to minimize diving time and is fitted with 
salvage connections for use in the event of interior flooding. 

Support Structure 

A structure is provided to support the Sealab n hull on the ocean floor. This structure is 
designed so as to provide approximately six feet of clearance underneath the hull for ease of 
entry. The base of this structure is designed to provide a maximvmi bottom bearing stress of 
300 lb/ft at maximum negative buoyancy. 



^Internal Pipe Size 



DESIGN OF THE SEAEAB U HABITAT 43 



Fixed Ballast 



A concrete deck is installed inside Sealab n from the entryway forward to provide a por- 
tion of the fixed ballast. The remainder of the fixed ballast is placed in trays underneath the 
hull. 

EQUIPMENT 

General 

All mechanical equipment to be installed in Sealab II (Fig. 24) was checked and certified 
for use in the ambient operational environment. Particular emphasis was placed on eliminating 
any materials which may introduce toxic fumes into the closed atmosphere. All equipment cav- 
ities or enclosures are vented for pressure equalization or are tested to prove a capability of 
withstanding the pressure of or permeation by the Sealab 11 atmosphere. Particularly all "an- 
eroid type" sensing elements were eliminated, since they are designed to operate only in stand- 
ard (air) at barometric pressures. All equipment was performance tested in the Sealab II 
environment and design capacities adjusted where necessary to compensate for the peculiar 
characteristics of the new environment, such as hyperbaric pressures, increased density, 
higher specific heat, increased thermal conductivity, etc. 

Water Closet 

The water closet is a standard marine type, Wilcox- Crittendon "Senior" model. 

Lavatory 

The lavatory is vitreous china, 17 x20 in. minimum size, and may be wall or cabinet 
mounted. 

Sinks 

Two sinks are required, one in the galley and one in the laboratory. The sinks are double 
basin, self-rim, porcelain enamelled steel and approximately 33 x 22 in. overall dimensions. 

Water Heater 

The water heater is electrically powered, quick recovery, and has a 50-gallon storage 
capacity. It is equipped with a pressure-temperature safety relief valve set at 100 psig relief 
pressure. Note: This setting can be accomplished under normal atmospheric conditions. The 
relief valve discharge was piped to a convenient overboard drain (see Chapter 9). 

Emergency Fresh Water Tank 

An emergency fresh- water tank was installed inside Sealab II to provide approximately 
150-gallon storage capacity. This tank will not be used as a pressure tank and is provided 
with an adequate vent to prevent pressure buildup while filling. It was constructed of CRES 
and properly sterilized for storage of potable water (see section titled "Plumbing and Sanitary 
Facilities"). 

Showers 

Two showers are provided in the entryway, starboard side. The showers are drained di- 
rectly overboard through the main entry hatch. 



44 DESIGN OF THE SEALAB II HABITAT 

Hookah Pumps 

Two hookah pumping units are suspended from the overhead, aft of the hatch in the entry- 
way. Due to late delivery of these equipments, they were mounted at Long Beach Naval Ship- 
yard. Four hull penetrations, one inch IPS by six inches long, threaded nipples, were installed 
in the after semi-elliptic head. These penetrations are located approximately six inches above 
deck level and spaced on four- inch centers horizontally about the longitudinal centerline. All 
threads are protected with pipe caps. 

Refrigerator- Freezer 

A combination refrigerator-freezer of approximately 10 cu ft storage capacity (5 cu ft 
refrigerator - 5 cu ft freezer) was installed in Sealab II. The refrigeration cycle is the con- 
ventional Freon gas system. Since the helium-rich Sealab II atmosphere is approximately six 
times as conductive as air, it is necessary to provide sufficient insulation to reduce heat gain, 
or an increased cooling capacity is required to compensate for the increased heat gain of a 
standard commercial insulation system. If mercury type temperature controls are utilized, 
these should be adequately protected against rupture (see Chapter 9) . 

Plumbing and Sanitary Facilities 

The supply piping is of conventional design for 125 psi service. Fresh water was supplied 
to Sealab from shore to provide a minimum flow of 10 gpm at a minimum pressure of 40 psi 
above ambient. Maximum (static) pressure did not exceed 75 psi above ambient. Pressure- 
relief valves for the supply system and water heater'were set at 100 psig. A 50-gallon water 
heater is installed (see Chapter 9). An emergency fresh- water storage tank of 150 gallon ca- 
pacity is installed for use in the event of failure of the shore water supply. This tank is pro- 
vided with a hose bibb for filling and draining and is vented. The emergency water tank is not 
connected to the Sealab water system, in order to prevent accidental usage of the emergency 
supply. The emergency tank may be drained and refilled periodically in order to maintain 
"fresh" tasting water. A hose bibb is installed in the supply system and located in the entry- 
way for this purpose and also for general washdown purposes. A 25-ft length of "garden" hose 
is provided. 

The sanitary system is of conventional design, gravity flow, overboard discharge. A 50-ft 
length of hose is provided for attachment (external) to the overboard sanitary discharge. This 
serves to keep the discharge opening below the water level in the entry trunk, thereby prevent- 
ing gas loss from Sealab, and conveys the effluent away from Sealab. Since it is impossible to 
vent the sanitary system externally, all vents are fitted with potassium permanganate or char- 
coal filters to remove odors from the vent gases. 

Air- Conditioning System 

The air-conditioning system provides the following functions and capabilities: 

Dehumidification - 18 gallons per day 

Ventilation - 1200 cfm 

Heat - 25 kva (see Electrical Specifications) 

CO2 Scrubbers - 1 Ib/hr (approximately 4600 cu in. LiOH) 

Charcoal Filter - to remove hydrocarbons, odors, and aerosols 

(approximately 2300 cu in.) 
Gas sampling and make-up - (see Breathing Gas Systems) 

It is desirable to obtain gas flow through the air-conditioning system with a single fan in 
order to reduce the number of electrical motors in the system. It is further desirable to en- 
close the one fan motor in a pressure- tight (5 psi over ambient) enclosure to reduce fire or 
contamination hazard. The distribution and return system is arranged so as to provide com- 
plete circulation of the Sealab atmosphere in order to eliminate any stagnant areas which might 



DESIGN OF THE SEALAB II HABITAT 



45 



create CO2 pockets or concentrations. Storage space is provided for replacement supplies of 
charcoal and LiOH. 



BREATfflNG GAS SYSTEMS 

General 

The breathing gases to be used to make up the Sealab II atmosphere are stored externally 
in 1,300-cu-ft cylinders (Fig. 25) (approximately 21 ft long and 9-5/8 in. O. D.) Storage pres- 
sures are nominally 2400 psi and all high pressure lines are designed for 3000 psi service. All 
breathing- gas systems are cleaned in accordance with BuShips specifications for breathing- 
oxygen service. Gases for the emergency make-up systems are supplied through the umbilical 
cord at a maximum pressure of 400 psi. A gas-control panel is provided and contains all com- 
ponents indicated on each drawing of the individual systems. This panel is located above the 
counter, port side, aft of the air-conditioning space, and has complete piping- diagram layouts 
of each gas system properly color- coded for ease of identification. The three pressure regu- 
lators plus one spare required in the oxygen, helium, and BIBB systems are of the type used in 
standard welding equipment. All regulators are identical, so as to provide inter changeability. 
These regulators are capable of providing the specified low pressure (gage) range by simple 
external adjustment in an ambient pressure of up to 140 psia. 




Fig. 25. Aquanaut Sheets checks fittings on the Sea- 
lab II externally mounted breathing gas cylinders 



46 



DESIGN OF THE SEALAB II HABITAT 



Oxygen System 

The automatic and manual oxygen systems are in accordance with Fig. 26. This system is 
designed for automatic (normal) operation utilizing a "Krasberg" POj sensor and servo valve 
supplied by Westinghouse Corporation. Provisions are also made for bypassing the servo valve 
for manual operation. The external storage bottles are piped to two separate manifolds of five 
and six bottles each. During operation, one bottle on each manifold was "on line" at all times, 
such that in case of failure upstream of the gas- control panel, a backup supply may be selected 
immediately inside Sealab. Note: Make-up oxygen shall be introduced into the discharge duct 
of the ventilation system downstream of the gas- sampling line. The oxygen input is downstream 
of the fan motor to reduce fire hazard and is in a high- velocity or turbulent region to provide 
complete mixing. 



MANUAL O2 MAKE-UP 
AUTOMATIC O2 MAKE-UP 



SCRUBBER-FILTER 
EXHAUST PLENUM -. 

PO2 SENSORaT 

I 
1 
) 

r" 



3000 PSI H.R 




MANUAL O2 MEASUREMENT-* 
2-200 CU FT BOTTLES 



7^ 



SERVO VALVE 

DISTRIBUTIONS, 
DUCT 



GAS CONTROL 
PANEL 




GAS FLOW 







NOTE: GAS SAMPLING LINE 
TO BE UPSTREAM OF 
O2 MAKE-UP 



STUFFING TUBE 

5- HULL (BOTTOM) 

02 STORAGE, EXTERNAL, II-I300CUFT 
BOTTLES ON TWO MANIFOLDS 



a<x- 


-^ 


u^ 


H 


^^<~ 


^ 


^^^?c- 


H 


n^^yC- 


^ 


b^ 


^ 



Fig. 26. Sealab II oxygen system 



Helium System 

The helium system is in accordance with Fig. 27. This system is designed to provide any 
make-up required in Sealab and is designed for manual operation. The ten external storage 
bottles are piped to a single manifold. During operation one bottle was "on line" at all times. 
The helium input is introduced into the air system upstream of the circulating fan to provide 
adequate mixing. 



DESIGN OF THE SEALAB II HABITAT 



47 



SCRUBBER - FILTER 
EXHAUST PLENUM- 



HELIUM MAKE-UP-^ 



3000 PSI 



H.P.^UP. 



0-300 PSI 



GAS CONTROL 
PANEL 



c-^ 



PO2 SENSOR 
t 



GAS FLOW 

-yt K^ 



-STUFFING TUBE 



cz> 



a 



szz> 



a 



'^— HULL (BOTTOM) 



O 






a 



o. 



a 



o 



He STORAGE, E X T E RN AL, 10 -1300 CU FT 
BOTTLES ON MANIFOLD 



<Z3 



3 



3 



<pCZI5 



Fig. Z7. Sealab II helium system 



Bibb System 

The Bibb system is in accordance with Fig. 28. The three external storage bottles are 
piped to a common manifold. During operation all three bottles were "on line" at all times. This 
system is designed to provide emergency breathing gases (premixed) in the event the Sealab 
atmosphere becomes contaminated. It will provide approximately 43 minutes breathing time 
for ten aquanauts. Internal manifolding shall be installed to provide quick- connective outlets 
(female or socket) as follows: 

10 - berthing space 

4 - galley space 

4 - lab space 

10 - entry way 

Ten "Calypso" Model No. 1050 single-hose scuba rigs are provided for use with the Bibb 
system. These equipments were modified by removal of the first-stage pressure regulator and 
the installation of a quick- connective fitting (male or plug end) to suit quick- connective fittings 
installed in Sealab. Note: The first-stage regulators removed from the Calypso rigs are to be 
retained for installation on emergency scuba bottles. 



48 



DESIGN OF THE SEALAB II HABITAT 



Ten 38-cu-ft scuba bottles with first- stage regulators (removed from Calypso rigs) and 
quick- connective fittings (female or socket) to be identical with Bibb system fittings installed 
in Sealab are provided and stored inside entry trunk of Sealab. These bottles may be utilized 
by the aquanauts to swim to the PTC in the event of emergency evacuation of Sealab. 



AFT TO QUICK -CONNECT 
OUTLETS (AUTO. SHUTOFF)]^ 
12 OUTLETS IN ENTRY 
SPACE a 4 IN LAB SPACE 



EMERGENCY BREATHING MANIFOLD 



3000 PS! H.R 



..R 0-300 PS I 
(120 PSI NOM) 



FWD, TO QUICK-CONNECT 
OUTLETS (AUTO, SHUTOFF) 
12 OUTLETS IN BERTH 
SPACE a 4 IN GALLEY SPACE 



_S-GAS CONTROL 
PANEL 



Ij_3- STUFFING TU 



K X > 



n. 



BE 
<— - HULL (BOT 



TOM) 



He (85%) - 02 (I5%)PREMIX STORAGE, EXTERNAL, 
3-1300 CUFT BOTTLES ON MANIFOLD 






Fig. Z8. Sealab II bibb system 



Emergency Helium, Air, and Oxygen Systems 



These systems are in accordance with Fig. 29. The emergency helium and air system 
will be utilized to provide helium or air from the surface in the event of failure or exhaustion 
of the self-contained helium supply. This system is also used for the surface (initial) charg- 
ing of Sealab. Gases are supplied through the gas-supply hose of the umbilical cord at 400 psig 
maximum pressure. The emergency oxygen system is utilized to provide oxygen from the sur- 
face in the event of failure or exhaustion of the self-contained oxygen system. This system is 
used as a gas- sampling system for surface monitoring of the Sealab atmosphere. Oxygen is 
supplied through the gas- sampling hose of umbilical cord of 200 psi maximum pressure. The 
gas- sampling intake is located in the outlet of the air-conditioning system upstream of the ox- 
ygen input in order to obtain sampling of well-mixed and filtered atmosphere. An additional 
gas sampling intake is provided via a 30-ft length of 1/4- in. I. D. hose for sampling at any de- 
sired point inside Sealab. 



DESIGN OF THE SEALAB II HABITAT 



49 




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Chapter 9 

ELEaRICAL AND ELECTRONIC SYSTEMS 
FOR THE SEALAB II HABITAT 



R. B. Porter 

U.S. Navy Mine Defense Laboratory 

Panama City, Florida 

INTRODUCTION 

The specifications for the electrical and electronic systems were divided into three sets 
of specifications: Electrical, Communications, and Data Recording. A fourth specification 
closely related to the electrical system was prepared for the electrical equipment to be used 
in the Sealab II habitat. In general the material and equipment specified were standard Navy 
items normally used in shipboard electrical systems. The use of commercial items was per- 
mitted and in some cases specified. The short lead time available precluded the design, de- 
velopment, and testing of any special items or equipment. The requirements specified for the 
three systems and the electrical equipment are outlined in the following paragraphs. 

REQUIREMENTS FOR ELECTRICAL SYSTEM 

General 

The power and lighting distribution systems are as specified herein and shall be in general 
accordance with Figs. 30 and 31. The system shall be ungrounded and insofar as practical 
shall be in accordance with applicable sections of General Specifications for Ships of the U.S. 
Navy. 

Supply Voltage 

The supply voltage will be 450-volt, 60-cycle, three-phase supplied from the staging vessel 
or from shore through an underwater transformer bank and junction box installed at the test 
site by Scripps Institution of Oceanography. A maximum of 75 kva will be available. 

Utilization Voltage 

All power-consuming equipment shall operate on one of the following: 

208-volt, three-phase or single-phase, 60 cycle 
440-volt, three-phase, 60 cycle 
115-volt, three-phase, 60 cycle 
115-volt, single-phase, 60 cycle 

230/115-volt, single-phase, 60 cycle (alternate for range in case suitable 440-volt 
range is not available) 

Electrical Load 

The estimated electrical load requirements as shown in Table 1 shall be used as a guide 
in designing the electrical system. 

50 



ELECTRICAL AND ELECTRONIC SYSTEMS 



51 



450 VOlT 
3 PMA^JE POWER 
PROM iTAiiiri& 
/E55 Ei_ 





DlSTRlBOTtON PfrNEL 
leS VOLT. 3-PHA^e BUi 






FOR l.l&HTm&, SIN&Lt 
PHASE POWER. AND IBO 
VOLT 3-PMA3t POWER 






- 








45 KVA TRANSFORMER 
BANK, i50 V0LT'208/\^O 
voir. THB.IE PHAbE 














S^CVA XFMR 

SifVCLt: PHAS£ 










fORVA 4S0 VOLT 
3- Phase 
HEAT LOAD 
























lOOAMP 500 VOtT 
DiaiRtt UTION PANEL 
3. PHASE CIRCUITS 




SKVA ASO 3 PHAit 

FOR 
WATIR HtATtR 






(0 KVA ^SO YOiT 
3- PHAit 
HtAT LOAD 





























100 AMP 5QO VOLT 
3 POLE TR>NiPE.K 
SWITCH 



L. 



SEA'^AB 



srftOiNc vessel. 
ShOB€ powe*^ 

CONNt Cl ( OTsI 



UNDERWATtR 
JUNCTION BOX 
txFMK BAMK. 
*iliCjr TO 450A 

I yo KvA 



AICO VOLTi 
SHORE POWER 

AT SCB.IPPS 



Fig. 30. Sealab II power system, block diagram 



Umbilical-Cord Connections 

The umbilical cord from the support vessel will be a composite bundle of air, gas, and 
gas-sampling hoses, and power and communication cables. Details of the umbilical cord are 
contained in Chapter 10. In addition to the power cable in the umbilical cord, a shore power 
cable shall be provided. 



The cables shall be permanently connected and shall enter the hull through pressure-proof 
stuffing tubes near the bottom of Sealab. The cables shall extend from the hull penetrations on 
the exterior of the hull to the top access trunk. Protective guards shall be provided for the ex- 
terior cable runs. The cable ends terminating inside Sealab shall be sealed to prevent the 
Sealab atmosphere from escaping through the cable jacket and around the conductors. The 
cable for supplying power through the umbilical cord shall be Navy type THOF-42. The length 
shall be as specified in the umbilical-cord specification. 

Shore Power Cable — The cable for supplying power from shore through an underwater 
transformer shall be Navy type THOF-42. A rod closing type Kellems grip shall be installed 
on each end of the shore power cable. A waterproof connector shall be installed on the surface 
end of the cable. The connector shall have a male insert. A mating connector shall be fur- 
nished to Scripps Institution of Oceanography for installation on shore power supply cable. The 
connector shall be capable of sealing on a 1.250-in. -diameter cable. Pin connections for cor- 
rect phase rotation shall also be supplied. 



52 



ELECTRICAL AND ELECTRONIC SYSTEMS 



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EJLECTRICAL AND ELECTRONIC SYSTEMS 



53 



Table 1 
SEALAB II ESTIMATED ELECTRICAL LOAD 



Load 


Power 
(va) 


Utilization 
Voltage 


Interior Lighting 


1500 


115 


Single Phase 


Exterior Lighting 


8000 


115 


Single Phase 


Electric Blankets, 8 to 180 va 


1440 


115 


Single Phase 


Berth Lights, 10 to 40 va 


400 


115 


Single Phase 


General Purpose Outlets 








Berthing Space 


1500 


115 


Single Phase 


Galley (2) 


3000 


115 


Single Phase 


Lab 


6000 


115 


Single Phase 


Refrigerator, 1/4 hp 


700 


115 


Single Phase 


Hookah Pumps, 1 hp 


2800 


115 


Three Phase 


Water Heater 


4500 


440 


Three Phase 


Range, 80% Demand 


5360 


220 


Single Phase 


Central Air Conditioning 








Blower (1 hp) 


1400 


115 


Three Phase 


Dehumidifiers 


1750 


115 


Single Phase 


Heat 


20,000 


440 


Three Phase 


Sump Pump, 1/4 hp 


700 


115 


Single Phase 


CO2 Scrubber (Back Up) 


1050 


115 


Single Phase 


Heat (Entrance Area) 


5000 


115 


Single Phase 


Total 


64,840 




Total 115 volt single- and three - 


phase load 


35.74 kva 


Total 220 volt single-phase load 




5.36 kva 


Total 450 volt three-phase load 




24.50 kva 


Total to be provided 65.10 x 115'^ 


I 


74.9 


kva 



Illumination Requirements 

General — Fluorescent fixtures shall not be used. Commercial 40-watt appliance lamps 
and 50, 75, and 100-watt rough-service lamps have been tested and have been found to be suit- 
able for the proposed operating depth. Other types may be used provided they are suitable for 
the proposed operating depth. 

Interior Lighting — The number and location of the lighting fixtures for general and detail 
illumination shall be that required to provide the initial average foot-candle values specified in 
Table I of Section 9640-2 of General Specifications for Ships of the Navy. The laboratory space 
shall be considered as a General Workshop for general and detailed lighting requirements. 

Interior Lighting Fixtures — The lighting fixtures shall be commercial type Russell and 
Stroll No. 370 and/or No. 351, or other suitable fixtures. The asbestos leads shall be replaced 
with Type B wire of Specification MIL-W-16878 or covered with Teflon sleeving. A pressure- 
equalizing hole shall be provided in each fixture to permit the glass globe to be removed after 
Sealab is pressurized. All fixtures except fixtures in head and lavatory shall be controlled by 



54 ELECTRICAL AND ELECTRONIC SYSTEMS 

conveniently located switches. Switches shall be Symbol 780.1 listed in NavShips 250-560-3. 
(Note: 50 and 75-watt bulbs may be used in Fixture No. 370, since the He atmosphere is a 
better heat conductor than air.) 

Low -Level Lighting — A red lighting fijrture for low-level lighting shall be installed in the 
berthing space. The fixture shall be selected from NavShips 250-560-3. 

Berth Lights — Incandescent berth lights shall be installed for each berth. The fixture 
shall be a suitable commercial type which encloses the bulb. The fixtures may connect to a 
convenience outlet or be permanently connected. Each fixture shall have an off-on switch. 

Hand Lanterns — Hand lanterns without relay, Symbol 100.2 of NavShips 250-560-3, shall 
be installed throughout the interior of Sealab n to provide a limited amount of illumination in 
the event of a power failure. The minimum number of installed lanterns shall be four, and they 
shall be located to illuminate the following areas: (a) main entrance trunk (2), (b) electrical 
power control area, and (c) the berthing area. 

Exterior Lighting — The exterior lighting shall consist of six semiportable lighting fix- 
tures. The fixtures shall be Standard Navy diving lights. Symbol 313, as shown on BuShips 
Dwg. 9000, S6405-7445. Suitable mounting brackets shall be provided at locations shown on 
MDL Dwg. 8656 to permit the lights to be installed after Sealab is on the ocean floor, or to 
permit movement to temporary locations. The lights located on the port and starboard side of 
lab space shall have 150 ft of cable outside the Sealab. The remaining four lights shall have 
50 ft of cable outside the Sealab. Suitable stowage shall be provided for the excess cable when 
the lights are mounted on Sealab. Some convenient means shall be provided to permit the lights 
to be installed after Sealab is on the ocean floor. Connectors capable of being plugged or un- 
plugged underwater may be used. Cables shall not be run through the entrance trunk. 

A switch shall be provided inside Sealab for each exterior light. Each switch shall be 
clearly labeled. If underwater receptacles are used, switches shall be Symbol 780.1 of NavShips 
250-560-3. If an interlocking switch and receptacle is used, it shall be Symbol 900.1 of NavShips 
250-560-3. 

Equipment and Material 

The equipment and material for the electrical system shall be as specified herein. Mis- 
cellaneous items not specifically listed shall be Navy or commercial items best suited for the 
application. 

Transformers — The transformers shall be dry. Naval Shipboard type in accordance with 
MIL-T-15108. Three 450-120 volt transformers of suitable size connected delta-delta, or 
delta-wye, shall be used to supply power for the lower voltage single- and three-phase loads. 
A 6-kva transformer bank or transformer shall be provided to supply 240-120 single-phase 
power for the electrical cook top if the unit will not operate on 440-volt three-phase or the 
lower voltage of the main transformer bank. 

All transformers shall be enclosed in a gastight compartment to prevent contamination of 
the Sealab atmosphere in case of overheating. Stuffing tubes shall be used for all cables enter- 
ing the compartment. The compartment should be built so that one side is formed by the shell 
of the vessel. The shell side shall not be insulated. A pressure-equalizing valve shall be pro- 
vided to equalize the pressure of the interior of the compartment during pressurizing operations. 
A temperature -indicating device shall be provided to monitor the inside temperature of the 
compartment near the center transformer. A circulating fan shall be installed in the trans- 
former compartment to provide forced circulation of the compartment atmosphere through the 
transformers in case of a temperature buildup. The fan may be manually or automatically 
controlled. 

Transfer Panel and 450-Volt 3-Phase Distribution Panel — The incoming power -transfer 
panel and 450-volt 3-phase distribution panel shall be similar to NWT Type panel. Symbol 2531, 
listed in NavShips 250-560-3. The number of circuits required shall be determined by the 



ELECTRICAL AND ELECTRONIC SYSTEMS 



55 



detail design. The transfer-switch breakers shall be 100 amp capacity. The power-distribution 
breakers shall be selected to protect the load served. At the option of the design activity, the 
transfer switch and the 450-volt, 3-phase distribution panel may be in separate enclosures. 

Power and Lighting Distribution Panels - The 115-volt power and lighting distribution 
panels shall be similar to totally enclosed type Symbol 994.3, 995.3, or 999.3 listed in NavShips 
250-560-3. The number and size of the panels required shall be determined in the detail de- 
sign. The rating of the circuit breakers shall be selected to protect the load served. 

Cable — The cable for the electrical system shall be type SGA of MIL-C-2194 and/or types 
covered in MIL-C-915. 

Stuffing Tubes — Stuffing tubes shall be standard Navy stuffing tubes listed in NavShips 
250-560-3. Pressure-proof type shall be similar to tubes shown on BuShips Dwg. 815-1197030. 

Interior Receptacle — The double receptacles installed throughout the vessel shall be 
grounded type and shall be Symbol 730.1 (commercial) listed in NavShips 250-560-3. Where 
receptacles controlled by a switch are required, Symbol 900.1 of NavShips 250-560-3 shall be 
used. Commercial plugmold or similar may be used in the lab space, providing provisions of 
Note 7 of BuShips Dwg. 9000 S6202 73980, Section 3, Sheet 57 are met. 

Waterproof Connectors — Waterproof connectors shall be any suitable commercial or Navy 
type. The following companies manufacture waterproof connectors: 

Cannon Electric Company, Los Angeles, California 

Marsh and Marine, Houston, Texas 

D. G. O'Brien, Inc., Natick, Massachusetts 

The manufacturer of the connector selected should be consulted for proper installation 
procedures. 

REQUIREMENTS FOR COMMUNICATION SYSTEM 

General 

Communication between the Sealab and the Communications Command Center (CCC) on the 
support vessel will be via a communications cable in the umbilical cord. The following modes 
of communication are to be provided: 

1. Helium Speech Unscrambler 

2. Electrowriter 

3. Television 

a. Closed Circuit Monitors 

b. Entertainment 

4. Audio, CCC to Sealab 

5. Audio, CCC to shore via Sealab 

6. F-M Music 

In addition to the communication modes, the following information will also be transmitted 
via the communication cable: 

1. Wedge Spirometer Output 

2. Trunk Water Level 

3. O2 Partial Pressure 

Unless otherwise specified, all equipment will be installed at Long Beach by U.S. Naval 
Ordnance Testing Station (NOTS) Pasadena. 



56 ELECTRICAL AND ELECTRONIC SYSTEMS 

Exterior Umbilical Cord Connection 

The communication cable shall be permanently connected through the hull with a pressure- 
proof stuffing tube near the bottom of the hull. The pressure -proof stuffing tube shall be simi- 
lar to those shown on BuShips Dwg. 815-1197030. The cable shall terminate in a suitable plug 
at the communication center inside Sealab. The cable end shall be sealed to prevent the Sealab 
atmosphere from escaping through the cable jacket and around the conductors. The exterior 
section of the cable shall extend from the hull penetration to the umbilical connection near the 
top of top access trunk. Protective guards shall be provided for the exterior cable run. 

Communication Cable 

The communication cable specified for the umbilical cord is Boston Insulated Wire Com- 
pany No. TV-33N or equal, neoprene jacket, O.D. 0.780 ft ± 0.015 in. Table 2 lists the recom- 
mended conductor usage. Cables required for other interior communication circuits shall be 
Navy or commercial types best suited for the application. 

Sealab Communication Center 

A section of the lab bench adjacent to the fan cabinet shall be used for the Sealab commu- 
nication center. A patch panel shall be designed and installed at this location to facilitate con- 
necting the various pieces of equipment at the test site. The panel shall have multi-pin recep- 
tacles for all multiconductor circuits and coax receptacles for the TV circuits. Each receptacle 
shall be labeled. Plugs shall be provided for each receptacle. Table 2 lists suggested recep- 
tacles or a particular receptacle if required to mate with an existing plug on the equipment. A 
panel shall be built and furnished to NOTS, Pasadena, for installation in the CCC van on the sup- 
port vessel. The panel shall be identical to the Sealab panel, except (a) a switch for the FM 
speaker is required, and (b) an Amphenol receptacle No. 67-02E14-5S or equal shall replace 
the two separate receptacles for the audio link to Sealab and shore. A mating plug shall be 
furnished. A wiring diagram shall also be furnished with the panel. 

Helium Speech Unscrambler 

The helium speech unscrambler is being provided by the Office of Naval Research (ONR) 
in cooperation with BuShips. The equipment will be shipped to NOTS, Pasadena. Three head- 
sets are being provided and are to be located as follows: Sealab Communication Center, galley, 
and berthing space. Cables shall be run to the galley and berthing space and terminated at a 
convenient location in a receptacle. The conductor and connector requirements are listed in 
Table 2. 



Electrowriter 

The electrowriter, consisting of a transmitting unit and a receiving unit, will be shipped to 
NOTS, Pasadena. The conductor and connector requirements are listed in Table 2. 

Television 

The TV units for monitoring and entertainment are being furnished by Scripps Institution 
of Oceanography. The conductor and connector requirements are listed in Table 2. 

FM Receiver 

The FM receiver and remote speakers will be provided by NOTS, Pasadena. The FM re- 
mote speakers shall time share the conductors in Quad 1 of the communication cable with the 
helium speech unscrambler headset (Table 2). A switch shall be provided on the patch panel 



ELECTRICAL AND ELECTRONIC SYSTEMS 



57 



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58 ELECTRICAL AND ELECTRONIC SYSTEMS 

for the Command Control van to switch off the FM circuit when using the helium speech un- 
scrambler. Receptacles and mating plugs shall be provided on the patch panels. Circuits from 
the patch panel to the speakers to be located in the berthing space and lab space shall be in- 
stalled. 

Audio, CCC to Sealab 

The audio link for two-way communication from the CCC to Sealab shall be a commercial 
intercom system, Bogen or equal. A two-station master shall be provided for the CCC and a 
remote unit at the Sealab Communication Center. The conductor and connector requirements 
are listed in Table 2. 



Audio, CCC to Shore via Sealab 

The second station on the master station provided in the previous paragraph shall be used 
for the audio link from the CCC to shore. A remote unit shall be furnished for the shore sta- 
tion. Conductor and connector requirements are listed in Table 2. 

Wedge Spirometer 

The wedge spirometer is being furnished by the Submarine Medical Center (SMC) and will 
be shipped to NOTS, Pasadena. Wiring diagrams will be furnished to all concerned at the ear- 
liest possible date. NOTS, Pasadena, will provide an extension cable from the patch panel in 
the CCC to the atmosphere van. An Amphenol plug 67-06J14-9S shall be installed on each end 
of the cable. The type of cable required will be specified later. Conductor and connector re- 
quirements are listed in Table 2. 

O2 Partial Pressure 

The Krasberg unit for determining the Oj partial pressure will be furnished by ONR and 
Special Projects. The equipment will be shipped to NOTS, Pasadena. Provisions are being 
made to monitor and record the Oo partial pressure remotely. The conductor and connector 
requirements are listed in Table 2. The installation of the unit and connections to the patch 
panel will be accomplished during the fitting-out period at Long Beach. 

Equipment Mounting Strips 

To facilitate the installation of communication and monitoring equipment during the fitting- 
out period, two slotted metal angle strips shall be installed on the overhead in the lab space, 
galley and berthing space. 

The strips shall be installed approximately 2 ft 2 in. on either side of the center line, the 
entire length of each space. Where interferences exist, the strips may be omitted. The strips 
shall be on the surface of the cork insulation. 

Circuits for Shore Equipment 

The following circuits shall be installed from a terminal box located near Scripps elec- 
tronic rack to the locations indicated for equipment to be installed later. 

Equipment Type Conductor Location 

Open Mike (3) Shielded Pair (3) (1) Berthing area 

(2) Galley 

(3) Lab 



Equipment 
Intercom 

Intercom 



ELECTRICAL AND ELECTRONIC SYSTEMS 

Type Conductor Location 

Shielded Pair (1) Sealab Communication Center 

Shielded Pair (1) Berthing area 



59 



REQUIREMENTS FOR DATA-RECORDING SYSTEM 
General 

The engineering and the environmental data specified herein will be recorded either in 
Sealab II proper or on shore through the facilities of the Scripps Benthic Laboratory. 



Engineering and Environmental Data to Be Recorded 

The following data is to be recorded: 
Item 

1. Power Usage 

2. Equipment Usage 

(a) Water heater (1) 

(b) Dehumidifiers (4) 

(c) Electric heaters 

(1) Baseboard banks (3) 

(2) Deck (1) 

(3) Radiant (4) 

(d) Refrigerator (1) 

(e) Freezer (1) 

3. Temperature, Interior 

(a) Trunk area 

(b) Lab area 

(c) Galley 

(d) Berthing area 

4. Temperature, Equipment 

(a) Refrigerator, interior 

(b) Freezer, interior 

5. Humidity, Interior 

(a) Trunk area 

(b) Lab area 

(c) Galley 

(d) Berthing area 

6. O2 Partial Pressure (PO2) 



7. Trunk HjO Level 



Recorder Location 



Sealab 
Sealab 



Shore 



Shore 



Shore 



Shore (monitor on support vessel) 
Shore (monitor on support vessel) 



60 ELECTRICAL AND ELECTRONIC SYSTEMS 

Power Usage Recorder 

A standard commercial three-phase watthour meter shall be provided and installed in Sea- 
lab and shall be connected on the load side of the transfer switches to record the total power 
consumed. If more convenient and economical, a watthour meter may be installed on the sup- 
ply side of each transfer switch. 

Equipment Usage Recorders 

Commercial, non-resettable, self-starting, synchronous, elapsed-time indicators shall be 
installed for all equipment listed under Item 2, Equipment Usage. The indicators may be in- 
stalled on the individual pieces of equipment or grouped at a convenient remote location. If 
indicators are grouped, they shall be labeled with the name of the equipment to which connected. 
The indicators shall register in hours and tenths of hours up to 9999.9. 

Interior Temperature Sensors 

The interior temperature of the Sealab at the locations specified in Item 3, Interior Tem- 
perature, will be recorded on shore through the facilities of the Scripps benthic lab. San Fran- 
cisco Naval Shipyard shall design and/or procure and install the necessary temperature sen- 
sors, amplifiers, and interior wiring. The temperature range of each sensor shall be 65° F to 
95°F. The benthic lab accepts an 0-7 vdc input with a preferred operating range of 1-6 vdc. 
The amplifiers shall be designed to produce a degree/volt output that will be within this range. 
The output cable from each sensor amplifier shall terminate in the terminal box located in the 
vicinity of the instrumentation cable trunk. 

Equipment Temperature Sensors 

The interior temperature of the refrigerator and freezer compartment will be recorded on 
shore through the facilities of the Scripps benthic lab. San Francisco shall design and/or pro- 
cure and install the necessary temperature sensors, amplifiers, and interior wiring. The tem- 
perature range of each sensor shall be approximately -10°F and +20°F of the designed temper- 
ature of each compartment. The output of each amplifier shall be designed to produce a 
degree/volt output that will be in the range of the benthic lab specified in the preceding para- 
graph. The output cable of each amplifier shall terminate in the temperature terminal box. 

Interior Humidity Sensors 

The interior humidity of the Sealab at the locations specified in Item 5, Interior Humidity, 
will be recorded on shore through the facilities of the Scripps benthic lab. San Francisco 
Naval Shipyard shall design and/or procure and install the necessary humidity sensors, ampli- 
fier, and interior wiring. The humidity range of each sensor shall be 50 to 100 percent relative 
(50 to 90 percent satisfactory if the above range is not available). The amplifiers shall be de- 
signed to produce a percent/volt output that will be in the benthic lab range. The cable from 
each sensor amplifier shall terminate in same terminal box provided for the temperature 
sensors. 

©2 Partial Pressure (PO2) Sensor 

The PO2 sensor is being furnished by NOTS. Two spare terminals in the terminal box 
shall be provided to facilitate connecting equipment at the test site. 

Instrumentation Cable Trunk 

An eight to ten inch pipe shall be installed through the hull at approximately frame 44 on 
the port side of the lab space to permit instrumentation cables to be brought in to the Sealab 



ELECTRICAL AND ELECTRONIC SYSTEMS 61 

from the benthic lab and other exterior equipment. The bottom end of the pipe shall extend to 
the same level as the bottom of the entrance trunk. The top end of the pipe shall be approxi- 
mately three feet above the deck. A removable watertight cover shall be provided. 

REQUIREMENTS FOR ELECTRICAL EQUIPMENT 

General 

The electrical equipment shall be standard Navy items or commercial items best suited 
for the application or which can be modified to suit the application. 

Electric Motor and Controllers 

The electric motors and controllers selected shall be in general accordance with Section 
9630-1 of General Specifications for Ships of the U.S. Navy. Commutator type motors shall not 
be used. Insofar as practical, motors selected shall be three-phase. The necessary manual or 
magnetic controllers shall be provided for each motor. Thermal overload protection shall be 
provided for each motor, including those furnished as part of a complete unit, either from the 
Navy supply system or commercial sources. The thermal protection shall be designed to pre- 
vent the motor from becoming overheated and contaminating the atmosphere. Fan motors 
should be oversized or have the pitch of the fan modified to compensate for the denser atmos- 
phere. Precautions should be exercised in the modification of the pitch of the fan blade of 
equipment cooling fans. 

Water Heater 

The water heater shall be a 50 to 52 gallon capacity, quick-recovery type. The preferred 
voltage is 440 volts, three-phase; however, a lower voltage rating may be used if a 440-volt 
unit is not available. The insulation shall be fiber glass or rock wool. 

Refrigerator 

The refrigerator shall have a net capacity of not less than 10 cu ft and not more than 14 
cu ft, and shall be divided into a freezer compartment and a refrigerator compartment. The 
freezer capacity shall not be more than 5 cu ft net. The refrigerator shall be capable of per- 
forming its normal function in an 80 percent helium atmosphere at approximately 110 psig. 

Cook Top 

The cook top shall consist of four electric heating units of approximately 1250 watts each. 
Each unit shall have a heat-control switch. Thermostatically controlled units are not required. 
The preferred voltage is 440 volts, three-phase; however, other voltages may be used if 440- 
volt units are not readily available. 

Radiant Heaters 

The four radiant heaters for the entrance area, as shown on MDL Dwg. 8656, shall be at 
least 1250 watts each. Each heater shall be controlled by a double-pole switch or the circuit 
breaker in the distribution panel. 

NOTE: Nutone Model 9290 was used in Sealab I and performed satisfactorily. 



62 ELECTRICAL AND ELECTRONIC SYSTEMS 

Bracket Fans 

The two bracket fans for emergency circulation will be furnished. Fans are Robin and 
Myers Model CG16-1/2-3, Cat. No. CG 16-1/2 361, 110-120 vac, 60 cycle, 0.70 amp. The fans 
are not to be installed but will be stowed aboard Sealab. 

Hookah Pumps 

The two hookah pumps will be furnished. The motors will be 1 hp, 440-volt, three-phase. 

Miscellaneous 

The following equipment will be used in Sealab. All equipment operates from a standard 
15-amp grounded receptacle. 

1. One rotisserie (1500 watts). (For use in galley.) 

2. Two portable electric heaters (1650 watts each). (Back-up heat if part of main system 
fails.) 

3. Bracket fans. 

No special circuits are to be installed for the heaters; however, the convenience outlet 
circuits should have the capacity to accommodate one heater. 



chapter 10 
UMBILICAL CORD FOR THE SEALAB II HABITAT 

W. B. Culpepper and R. B. Porter 

U. S. Navy Mine Defense Laboratory 

Panama City, Florida 

INTRODUCTION 

The purpose of the umbilical cord is to provide utilities to the Sealab II habitat from the 
support vessel. The power and communication cables were permanently attached to the Sealab 
and penetrated the hull through pressure-proof stuffing tubes. The hose components were con- 
nected to piping installed on the exterior of the hull with two-way shut-off quick-disconnect type 
connectors. The short lead time available precluded the design and testing of suitable under- 
water connectors for the power and communication cables which would have permitted the um- 
bilical cord to be completely disconnected from the Sealab. Also, time did not permit the de- 
sign of a special communication cable with the proper number and type of conductors required. 
In this case, the best commerical item available was specified. The umbilical-cord require- 
ments specified are outlined in the following paragraphs. 

REQUIREMENTS FOR THE UMBILICAL CORD 

General 

The umbilical cord from the support vessel to the Sealab will contain hoses for compressed 
air, gas supply, and gas sampling, and cables for power and communications. The compressed- 
air hose will provide 400 psig air for pneumatic tools. The gas-supply hose will supply, at 400 
psig, the initial helium charge, make-up helium, and breathing air. The gas-sampling hose will 
be used to obtain Sealab atmosphere samples and to supply emergency oxygen. The power cable 
will supply 450-volt, 3-phase power from the support vessel. The communication cable will pro- 
vide communication, closed-circuit television, and environment data circuits from Sealab to the 
communication command center on the support vessel. The power and communication cables 
will be permanently connected to the Sealab. Each hose component will have a quick-disconnect 
type connection on each end. All hose connections on the Sealab end will be made in a central 
location near the top entrance trunk. The connections at the support-vessel end will also be 
made at at central location on the vessel. 

Design 

The umbilical cord shall have a nominal length of 350 ft. All components shall be compactly 
arranged (Fig. 32) to form a compact, easily handled bundle. The bundle shall be covered over- 
all with a woven cotton or nylon braid, a hand-sewed canvas jacket, or bound at sufficient in- 
tervals to insure that a compact bundle is maintained. The method of binding shall be such that 
the individual components are not damaged and a relatively smooth surface is maintained. A 
Kellems stainless steel single-weave grip, or equal, shall be installed on each end to prevent 
strain on the connections. A double wrap of cotton canvas shall be placed under each grip to 
prevent damage to the components. The eye of the grip on the Sealab end of the umbilical cord 
shall be eight feet from the end. A six foot, 7/16-in stainless steel wire rope pendant shall be 
provided to connect the grip to the Sealab. A suitable staple or pad eye shall be installed on the 
top entrance trunk near the umbilical connections. The cable grip on the upper end shall be a 
Kellems stainless steel Rod Closing Grip, or equal, and shall be placed on the cord near the end 
for shipping purposes only. Naval Ordnance Test Station (NOTS), Pasadena, will position the 
grip at the time of lowering. Floats will be attached to cable by NOTS, Pasadena, to obtain a 
slight positive buoyancy. 

63 



64 UMBILICAL CORD 




BINDING 



Fig. 32. Cross section of umbilical cord 

Details of Components 

The individual components of the umbilical cord shall be as specified herein. 

1. Electrical Power 

a. Cable . The power cable shall be Navy type THOF-42 of MIL-C-915, or a suitable com- 
merciaT equivalent. The cable shall be 350 ft plus additional length to reach from the top access 
trunk to the termination point inside Sealab. The cable shall be in one continuous length. 

b. Stuffing Tube, Sealab End . The power cable shall be permanently connected and shall 
enter the hull through pressure -proof stuffing tubes near the bottom of the hull. The pressure- 
proof stuffing tube shall be similar to tubes shown on BuShips Drawing 815-1197030. 

c. Plug, Support-Vessel End . The plug shall be a Crouse-Hinds Catalog No. AP20465. The 
plug shall have a male insert. A protective cap, Crouse-Hinds Catalog No. CPK-104, shall be 
provided and secured to the plug with a chain or small stainless steel cable. 

2. Communications 

a. Cable. The communication cable shall be Boston Insulated Wire Company No. TV-33N 
or equal. Conductor usage is outlined in the communication specifications. The cable shall be 
350 ft, plus additional length to reach from top access trunk to termination point in Sealab. The 
cable shall be in one continuous length. A 150-ft continuous length of the cable shall be furnished 
to NOTS, Pasadena. 

b. Stuffing Tube, Sealab End . The communication cable shall be permanently connected 
and shall enter the hull through pressure-proof stuffing tubes near the bottom of the hull. The 
pressure -proof stuffing tube shall be similar to tubes shown on BuShips Drawing 815-1197030. 

c. Plug, Support Vessel End. The plug on support vessel end shall be waterproof with cap 
and chain or provided with a waterproof boot. 

3. Gas Sampling 

a. Hose . The gas-sampling hose shall be a l/4-in. I.D. x 19/32-in. O.D. welding hose for 
oxygen service, 250 psig working pressure, and shall be Gates No. 16B or equal. The hose shall 
be in one continuous length. 



UMBILICAL CORD 65 

b. End Fittings . A two-way sliut-off quick-connecting fitting shall be installed on each 
end of the hose. The fittings shall be l/4-in. Roylyn Incorporated Series 1300, or equal. Ma- 
terial may be brass or corrosion-resistant steel. 

The Sealab end shall have a nipple-type fitting. 

The support vessel end shall have a coupling-type fitting. 

A cap or plug shall be provided for each end of the hose and secured to the hose with a 
chain or small stainless steel cable. The cap and plug should be of the same material as the 
end fitting; however, aluminum may be used with corrosion-resistant steel fittings. 

c. Cleaning . Upon completion of the installation of the end fittings, the hose shall be thor- 
oughly cleaned for oxygen service. The cap and plug shall be installed to prevent the interior 
from becoming contaminated during handling. 

4. Gas Supply 

a. Hose . The gas supply hose shall be 3/4-in.I.D. x 1-1/4-in. O.D. with a minimum work- 
ing pressure of 400 psig and shall be Weatherhead H- 16 or equal. The hose shall be in one 
continuous length. 

b. End Fittings . A two-way shut-off quick-connecting fitting shall be installed on each end 
of the hose. The fittings shall be 3/4-in. Roylyn Incorporated Series 1300 or equal. Material 
may be brass or corrosion-resistant steel. 

The Sealab end shall have a coupling type fitting. 

The support-vessel end shall have a coupling type fitting. 

A plug shall be provided for each end of the hose and secured to the hose with a chain 
or small stainless steel cable. The plugs should be of the same material as the end fitting; 
however, aluminum may be used with corrosion-resistant steel fittings. 

c. Cleaning . Upon completion of the installation of the end fittings, the hose shall be thor- 
oughly cleaned for helium and breathing air service. The plugs shall be installed to prevent 
the interior from becoming contaminated during handling. 

d. Color Coding . Both ends of the hose shall be color coded to distinguish the gas-supply 
hose from the air-supply hose. The connection on Sealab shall also be color coded. 

5. Air Supply 

a. Hose . The air-supply hose shall be 3/4-in. I.D. x 1-1/4-in. O.D. with a minimum work- 
ing pressure of 400 psig and shall be Weatherhead H-16 or equal. The hose shall be in one 
continuous length. 

b. End Fittings . A two-way shut-off quick-connecting fitting shall be installed on each 
end of the hose. The fittings shall be 3/4-in. Roylyn Incorporated Series 1300 or equal. Mate- 
rial may be brass or corrosion-resistant steel. 

The Sealab end shall have a nipple -type fitting. 

The support vessel end shall have a nipple -type fitting. 

A cap shall be provided for each end of the hose and secured to the hose with a chain 
or stainless steel cable. The caps should be of the same material as the end fitting; however, 
aluminum may be used with corrosion-resistant steel fittings. 

c. Cleaning . Upon completion of the installation of end fittings, the hose shall be cleaned 
by purging with compressed air to remove any foreign particles from the interior of the hose. 
The caps shall be installed upon completion of cleaning. 



66 UMBILICAL CORD 

d. Color Coding. Both ends of the air supply hose shall be color coded to distinguish 
the air supply hose from the gas supply hose. The connection on Sealab shall also be color 
coded. 

UMBILICAL CONNECTIONS ON SEALAB 

Power and Communication 

The cable connections for power and communication shall be as specified in the Electrical 
System and Communication System Specifications. 

Gas Sampling and Gas and Air Supply 

A quick -connecting coupling type fitting shall be installed on each Sealab gas line. Each 
coupling shall mate with its respective hose nipple in the umbilical cord. Plugs shall be pro- 
vided and secured to the gas lines with chain. The plugs should be of the same material as the 
coupling; however, aluminum may be used with corrosion-resistant steel fittings. 

UMBILICAL CONNECTIONS ON SUPPORT VESSEL 

Power 

NOTS, Pasadena, will provide and install the mating receptacle and circuit breaker on the 
support vessel. The receptacle and circuit breaker shall be a Crouse-Hinds Catalog No. 
DVR75-2042-WT125-3. To insure proper phasing, pin-connection information shall be fur- 
nished by San Francisco Naval Shipyard (SENS) to NOTS, Pasadena. 

Communications 

A mating receptacle for the communication-cable plug with a water -proof cap and chain 
shall be furnished to NOTS, Pasadena, for installation on the support vessel. The receptacle, 
or sufficient details for installation plans, should be furnished to NOTS, Pasadena, as early as 
possible. SENS shall furnish a pin connection schedule to NOTS, Pasadena. 

Gas Sampling and Gas and Air Supply 

Quick-connecting nipples which mate with the coupling on the respective hoses, or suffi- 
cient details for the installation plans, shall be furnished to NOTS, Pasadena, for installation on 
the support vessel as early as possible. The couplings furnished shall be suitable for connect- 
ing to pipe identical to those in the umbilical. Hose color-code information shall also be pro- 
vided so that the connections on the support vessel may be coded in the same manner. 

NOTE: Hansen Manufacturing Company hose fittings. Series 2-HK and 6-HK as applicable, 
may be used in lieu of Roylyn type specified. 



chapter 11 
THE DESIGN, CONSTRUCTION, AND OUTFITTING OF SEALAB II 

Malcolm MacKinnon III 

San Francisco Bay Naval Shipyard 

San Francisco, California 

DESIGN PHILOSOPHY 

In the middle of January 1965, Hunters Point Division of the San Francisco Bay Naval 
Shipyard was approached with an interesting proposal. Could it undertake the design, construc- 
tion, and outfitting of an underwater habitat to be called Sealab E? Acceptance was given even 
though it was apparent that this was a marked departure from normal. The normal tasks of a 
shipyard are the construction, conversion, and repair of Naval Ships. There would be none of 
the clean-cut, detailed specifications and contract plans a shipyard normally receives when 
embarking on the construction of a prototype design. 

This project was in the realm of applied research and involved a large number of activities 
and people. Extensive studies in many areas for equipment selection and arrangement were 
precluded by time and economic reasons, and empirical results of precious tests were relied 
on and used. Naturally, the most significant of these prior tests was Sealab I. 

With the initial proposal came several parameters. Sealab II was to be a habitat capable 
of housing 10 men at a depth of 250 ft for a period of 30 days. Thus, complement, working 
depth, and duration were established directly from the basic goals of the project. 

In addition, much experience in the hitherto nonexistent field of underwater habitat design 
and construction was obtained by the Navy's Mine Defense Laboratory through its efforts in 
support of Sealab I. The assistance and guidance provided by MDL in early design phases were 
invaluable. Many equipment and installation specifications came directly from MDL. 

A great deal of the equipment utilized in Sealab I was "off-the-shelf" and of the mail-order- 
house variety. The fact that it functioned well in Sealab I, and a tight budget and schedule for 
Sealab n, influenced selection in many instances. 

The effect of feedback from Sealab I on basic design was considerable, and the following 
major design parameters were obtained, most resi^lting from operational difficulties experi- 
enced in Sealab I. 

1. Sealab II was to be a pressure vessel capable of being pressurized prior to submergence 
to bottom pressure. 

Reason : Sealab I was a nonpressure vessel and was flooded more than once while being 
lowered while keeping internal gas pressure higher than hydrostatic. 

2. Submergence and bottom emplacement were to be done with Sealab n in an unoccupied 
condition. 

Reason : There would be less danger of personnel casualty if anything went wrong during 
pressurization and lowering. The importance of personnel safety was held paramount. 

3. The pressure vessel was to be cylindrical, approximately 50 ft long and 12 ft in diameter. 

Reason : The size of Sealab I and the already fixed complement of Sealab n indicated that 
this should be close to an optimum size and shape. 

67 



68 DESIGN, CONSTRUCTION, AND OUTFITTING 

4. The arrangement should include four separate areas: entry, laboratory, galley, and 
living space. 

Reason : This basic arrangement worked well with Sealab I. 

5. The atmosphere was to consist of approximately 85 percent helium, 4 percent oxygen, 
and 11 percent nitrogen. 

Reason : Controlled experiments and experience in Sealab I confirmed this to be a proper 
mixture to minimize narcosis, support life, and preclude complete air purging. 

6. Certain effects of helium were to be accounted for, primarily in the heat transfer area; 
the coefficient of heat transfer of helium being approximately six times that of air. Extra in- 
sulation must be provided. 

Reason: Heat losses were not calculated in Sealab I, and no controlled tests were run. The 
refrigerator, a thermal electric type, never operated satisfactorily. 

7. Temperature was to be held at 88° F and humidity at 60 percent relative. 
Reason : These seemed comfortable in Sealab I. 

8. Primary power was to come from the shore, secondary power from the surface staging 
vessel as part of the umbilical cord. Communications, secondary gas supply and sampling, 
and compressed air for external tools used were also to come down the umbilical. 

Reason : Assuming the integrity of the primary power source, the staging vessel could de- 
part and not cause an immediate abort or dangerous situation. Primary gas supply was from 
an external bank of bottles. Sealab I was terminated due to impending heavy weather. This 
development would make Sealab U more independent. 

9. There were to be a maximum number of portholes with the capability of seeing the bot- 
tom periphery of Sealab n. 

Reason: A near -fatal accident occurred in Sealab I. An unconscious man was rescued 
only when his bottles bumped the side of Sealab I; he was not visible from within. 

10. The atmosphere-water interface was to be as close to the bottom as possible. 

Reason : With no good data or information as to the extent of excursion dives deeper than 
saturation pressure, deeper depths could be reached from a higher saturation pressure. 

11. Reduction of the interior volume was to be made wherever possible by use of interior 
tanks, dead spaces, etc. 

Reason : Any decrease in interior volume was a decrease in the amount of helium required 
and thus a cost savings. 

12. Sealab n was to be painted white. 

Reason: The international orange of Sealab I would not have the acuity that white does 
underwater; hence easier sighting in marginal visibility conditions. 

There were a few other more minor considerations but the afore -mentioned were about 
the extent of information the shipyard received in the forms of design parameters. 

It became apparent very early that the biggest problem area in Sealab I was in the sub- 
merging operation. Railroad axles at 300 lb each were used as variable ballast. These were 
loaded by hand, and when sufficient negative buoyancy was reached, lowering was by a sling 
and whip arrangement from a crane on the surface. A 9- in. nylon line was used, and the effect 
was similar to a huge yo-yo on a rubber band. Once on the bottom, additional axles were added 



DESIGN, CONSTRUCTION, AND OUTFITTING 69 

to increase negative buoyancy. To eliminate this unwieldy method of ballasting, Sealab II was 
designed along submarine principles. The variable ballast would be water, stability would be 
maintained during all phases of the submerging operation, and negative ballast on the bottom 
to insure firm seating would also be water. NOTS Pasadena developed a winch-counterweight 
lowering system (Chapter 18) that made lowering against negative buoyancy feasible and de- 
sirable. Flooding had to be controlled simply and externally, since Sealab in this phase of 
operation was unoccupied and sealed. 

The condition requiring full working pressure internally at the surface made the Sealab 11 
cylinder an internally pressured nonfired vessel under the ASME Boiler Code. The code gov- 
erns the structural design, construction, tests, and inspection. The tables in the code indicated 
that one-inch-thick mild steel was sufficient for a working pressure of 125 psi, ample for the 
desired 250 ft. A structural- strength test, hydrostatically, to 1-1/2 times working pressure was 
also required. The end cappings for the cylinder were required to be ellipsoidal dished heads 
of proper curvature and depth. Their unique method of fabrication will be discussed later. 

The use of water as variable ballast and the desire for reduction in internal volume to save 
helium combined to provide internal ballast tanks. These were built into the overhead of the 
cylinder with sufficient capacity to allow proper reserve buoyancy on the surface and adequate 
negative buoyancy on the bottom, as previously discussed. The structural details necessitated 
making these tanks "soft", i.e., incapable of withstanding pressure differentials in excess of 
15 psi across their lower boundary. 

To preclude the necessity for a porthole (viewing port) capable of withstanding full internal 
pressure and to allow large (24-in.) ports, structural covers were provided internally to con- 
strain the pressure. When opened on the bottom they then exposed the port viewing glass to a 
pressure differential of slightly over 6 psi. This allowed the use of 1-in. plexiglas as the 
viewing-glass material. 

Previous data on equipment behavior in helium existed only in what could be obtained from 
Mine Defense Laboratory observations during Sealab I. Many commercially obtainable items 
functioned well, and this fact was accepted, tempered wherever possible by actual tests prior 
to any operational certification. As an example, commercial dehumidification units used ap- 
parently successfully in Sealab I. The same type units were procured and tested in helium at 
the Sealab II working pressure. It was noted during operational test that the compressor motor 
did not function properly. The malfunction was traced to a metallic relay in the motor start 
circuit that apparently changed its characteristics when operating in helium. Replacement 
with a sealed-unit relay restored normal operation. The rated capacity of 47 pints/day was 
never conclusively checked, however. A standard Navy-type refrigerator-freezer was pro- 
cured, additional insulation added, and the unit was tested in helium at working pressure. The 
thermal sensors in the refrigeration compartments were of the fluid-filled bulb type and would 
have crushed under the extreme pressures. Once these were replaced with thermocouple type 
sensors the refrigerator and freezer functioned properly. 

No data were available on heat losses and heat input during Sealab I, although qualitatively 
the aquanauts seemed comfortable at a temperature of 85° - 90° F at relative humidities between 
60 and 70 percent. It was obvious that these observations were all that was readily available to 
design the heating dehumidification, and insulation systems. A psychrometric chart for a He- 
Nj - O2 atmosphere was nonexistent. A qualititive analysis indicated that since ambient tem- 
peratures for Sealab 11 would be 20° to 30° F cooler than for Sealab I a much higher heating 
capacity (needed also to allow for many more men and a larger volume) and more insulation 
were required. Consequently, 25 kw of heat were provided and 2 in. of cork insulation on the 
inner surface of the shell were installed. These perforce were based on the most rudimentary 
qualitative analysis. A concrete deck was used for several reasons: 

1. Structurally simple and economical 

2. Provided additional ballast 

3. Reduced further the internal cubic 



70 DESIGN, CONSTRUCTION, AND OUTFITTING 

4. Provided insulation 

5. Enabled the use of radiant heating by embedding several runs of mineral insulated (MI) 
heating cable in the concrete. Additional heating was installed in the form of household con- 
vection baseboard and overhead radiant heaters. 

The ventilation system was modeled after a standard submarine system. Atmosphere 
treatment was determined to be sufficient if lithium hydroxide (LiOH) CO, scrubbers and char- 
coal filtration were used. The major effort in this regard was to properly channel the supply 
and return atmosphere to optimize treatment. 

Thus it is seen that the design philosophy involved in the development of Sealab II was very 
loose and flexible, based on a few supplied parameters and tempered by empirical data, eco- 
nomics, and time. Since Sealab II was a complex total project, very few design decisions were 
independent; most affected many other project team members, making this project a good prob- 
lem in systems engineering. Time and geographic distance precluded lengthy conferences on 
design decisions. Mostly the decisions were made locally, members of the team informed, and 
if no objections were heard in a reasonable length of time, production commenced. The results 
of these philosophies and decisions, the vessel itself and its characteristics, will be discussed 
in succeeding sections. 

DETAILS OF CONSTRUCTION 

The construction of Sealab II was generally a routine shipyard task with a few interesting 
exceptions. The production schedule was extremely tight, but not unlike any other more con- 
ventional shipyard project. Standard shipyard organization and practices were used throughout. 

The ASME Boiler Code under which the main cylinder was constructed provides for cer- 
tain procedures to be followed in assuring adequate quality. The steel selected for the main 
structure was 1- in .-thick mild steel, Grade M, of Military Specification MIL 5-16113 and, as 
such, received extensive testing at the rolling mill. The plate was ultrasonically inspected 
locally to check for laminations, and other specifications were spot checked. Welding was 
performed in accordance with current procedures for mild steel (AISI 1015-1025). All welds 
were radiographed, and films were evaluated according to the latest standards. All welds were 
defect-free. 

After fabrication of the basic structure, a hydrostatic test to 1-1/2 times working pressure, 
190 psi, was applied to test for strength. This was done prior to outfitting with fresh water to 
minimize any harmful effects. After installation of all piping systems and upon completion of 
all hull penetrations, a tightness test at working pressure was conducted using air. Helium 
was not used due to economic and time restrictions. 

In general, standard shipyard procedures were used in all phases of construction and test- 
ing. Quality -control procedures commensurate with those employed on normal shipyard work 
were invoked. 

As mentioned previously, the schedule was very close and would surely have been missed 
if it were not for the rapid solution of many production and procurement problems. Fabrica- 
tion of the large (24 in.) portholes was extremely difficult, since tolerances were very close 
and hard to maintain in the face of normal welding distortions. Not the least of the procure- 
ment problems involved the ellipsoidal dished heads used to cap the main cylinder. 

Once design specifications were set, contract bids were let to the normal suppliers of these 
large dished heads. The production schedule demanded a 30 to 45 day delivery. None of the 
major steel companies, the normal sources, could begin to touch this time frame. The large 
size of the heads, coupled with a rash of back orders due to an inpending steel strike, made 
normal procurement impossible. The earliest delivery that could be expected was five to six 
months, after the scheduled submergence of Sealab n. 



DESIGN, CONSTRUCTION, AND OUTFITTING 71 

Fortunately the shipyard maintains the Navy's West Coast Shock Testing Facility and thus 
has had a fair amount of experience in underwater explosions. The use of the energy of an 
underwater explosion to form metal is a noval idea, used sparingly in the past to form rela- 
tively small and simple pieces. The energy of explosion is transmitted as a pressure pulse 
through the water, forming the steel against a female die. The forming process lasts only a 
few milliseconds. The employment of this process to form large and complex sections like 
these dished heads was hitherto never attempted anywhere. Expedience and necessity being 
the parents of invention, the decision was made to attempt this quantum jump in the technology 
of metal forming. 

Immediately several problems became apparent: die design and construction, including 
curing of the concrete, handling and rigging, and configuration and size of the explosive charge. 
Briefly, a large die, 14-1/2 ft in diameter and 5-1/2 ft high, filled with a special-formula quick- 
curing concrete, was designed and built. A blank of steel was placed over the die and a vacuum 
drawn under the blank. This vacuum is extremely important, since any entrapped gas would have 
to vent, wrinkling the edges of the piece. One hundred pounds of C-4 plastic explosive were 
distributed in two concentric rings and a lumped central charge. The calculations for charge 
configuration, size, and standoff distance were extremely complex and important, as was the 
depth of water at detonation. 

The entire assembly, weighing 60 tons, was lowered 30 ft beneath the surface of San Fran- 
cisco Bay using the shipyard's large gunning crane. There the explosive was detonated, and in 
approximately 0.004 sec the first dished head for Sealab II was formed. 

The results were phenomenally good, and only minor straightening in certain areas was 
required. The heads checked dimensionally within 1/16 in. on the diameter and within 1/4 in. 
on the contour, well within specifications. The metal did not thin at all, and thickening by ap- 
proximately 0.075 in. occurred at the rim where stresses were highest. 

A detailed metallurgical analysis was conducted, comparing the stock plate, the place after 
forming, and the plate after stress relieving. As expected, the severe cold working of the ex- 
plosive forces embrittled and toughened the plate. Stress relieving restored most of the orig- 
inal metallurgical properties. 

The expense of die fabrication was considerable, but once made it can be reused. Die life 
can be made excellent, and once eight heads are formed the process becomes attractively com- 
petitive. 

The significance of this feat can best be illustrated by excerpts from a UPI story in the 
Berkeley, California, Gazette, dated Nov 18, 1965. 

"Denver (UPI) - A metal shaping process ... is being studied by Martin Co. and Denver 
University scientists for possible use in forming missile domes, side plates for ships, and 
other large structures. 

The technique was demonstrated Wednesday with the production of. . .ash trays. 

It involved the placing of a sheet of metal across a die or mold, then submerging the 
mold and metal in water. An explosive charge was detonated a few inches away, beneath the 
water, causing a shock wave to blast the metal into the mold. 

The experiment is being conducted under a one million dollar government grant by 
DU's Denver Research Institute and the Denver division of the Martin Company. It is ex- 
pected to take three years to prove or disprove the process." 

Figures 33 through 44 on the succeeding pages illustrate the process. 



72 



DESIGN, CONSTRUCTION, AND OUTFITTING 




ni, '-^v-iaBSSHsg--. 



Fig. 33. Plaster of paris male mold being finished 




Fig. 34. Steel die casing is lowered onto fiber glass lining 



DESIGN, CONSTRUCTION, AND OUTFITTING 



73 



>>m)^x'**"« 







Fig. 35. I-beam structure forming bottom of die, concrete being poured 




Fig. 36. Concrete is screeded and bottom of die is capped 
airtight with -steel plate 



74 



DESIGN, CONSTRUCTION, AND OUTFITTING 




Fig. 37. Steel blank is clamped in place on top of 
die with dogged hold-down ring 




Fig. 38. Ring-shaped explosive charges 
being mounted on die assembly 



DESIGN, CONSTRUCTION, AND OUTFITTING 



75 




Fig. 39. Sixty-ton die assembly is 
lowered into San Francisco Bay to 
30 -ft depth 




Fig. 40. Spray dome at instant of detonation 



76 



DESIGN, CONSTRUCTION, AND OUTFITTING 




Fig. 41. Formed blank immediately after lift up 




Fig. 42. Formed blank immediately after being removed from die 



DESIGN, CONSTRUCTION, AND OUTFITTING 



77 




Fig. 43. Waste fringe of piece is trimmed before stress relieving 




Fig. 44. Dished head is welded in place 



78 



DESIGN, CONSTRUCTION, AND OUTFITTING 



SEALAB n CHARACTERISTICS 

Hull Exterior 

Sealab II is essentially a nonpropelled submarine built to withstand an internal working 
pressure of 125psi (Fig. 45). It is a cylinder of one inch thick mild steel, 12 ft in diameter and 
57-1/2 ft long. The cylinder is surmounted by a conning tower 8 ft in diameter and 7-1/2 ft 
high. The conning tower provides dry access when surfaced as well as reserve buoyancy dur- 
ing the pressurizing operation, but is designed to withstand aAp of only 15 psi. 




B TOWING 
- CHOCK 



ESCAPE HATCH 



Fig. 45. Sealab II exterior 



The cylinder is set in a cradle-like structure with trays underneath for permanent lead 
ballast stowage. A walking flat is provided around the conning tower and extending fore and 
aft. Variable lead ballast is stowed under this flat for ready access to adjust final trim if 
necessary. 

Access while on the bottom is through a 48-in. diameter hatch aft. Entry is from the sea, 
into a protective anti-shark cage, up a sloping ladder, though the water-atmosphere interface 
in an 8-ft-square access trunk, and into the main cylinder. The water level in the access 
trunk is maintained by regulating the internal Sealab pressure. The trunk is designed to allow 
sufficient volume to accommodate the severest expected tidal change. 



DESIGN, CONSTRUCTION, AND OUTFITTING 



79 



Emergency exit is forward through a 30-in. hatch. Access on the surface is through the 
upper conning tower hatch, a 30 psi surface ship weather deck hatch, and the lower hatch, a 
30-in. hatch. The 48-in. main access hatch was specially fabricated, while the two 30-in. hatches 
are standard submarine escape trunk side hatches. 

Lifting pads are provided for both the dry maximum weight lift and the negative buoyancy 
lowering. Special slings are designed for each operation. Towing chocks are provided fore 
and aft. 

When on the bottom Sealab n is 13 tons negative and the bearing surfaces, two pads extend- 
ing athwartships fore and aft, are designed for 300 psf, the bearing strength of the bottom at 
the site. Corner spades 15 in. in depth allow a firm implacement and increase resistance to 
sliding. No provision is made to level the pads, such leveling is the task of the occupants if 
possible by a washing process using compressed air and water. 

Stowage racks for 24 - 1300 cu ft gas bottles are provided port and starboard forward. 
The bottles contain make-up helium (10), make-up oxygen (11) and a helium -nitrogen-oxygen 
mixture for emergency breathing (3). 

There are 11 viewing ports each 24 in. in diameter. These ports are designed to withstand 
15 psig internal pressure and are protected at full internal pressure by hinged steel covers. 
An equalizing line allows maintenance of a Ap = across the glass while submerging. This 
line is capped at depth and the steel covers opened. 

Hull Interior 

The variable water ballast tanks are three feet deep and located in the overhead (Fig. 46). 
These tanks are "soft" tanks, i.e., the bottom boundary cannot withstand aAp of greater than 
15 psi. These tanks provide, with the conning tower, the negative buoyancy necessary for ini- 
tial submergence and lowering, and the negative buoyancy necessary for firm seating on the 
bottom. 



VAR. LEAD BALLAST 




CONNING 
TOWER 

II. TONS 




VAR LEAD BALLAST 


1 2.5 TONS 1 


1 2.5 TONS 1 


/ TANK NO 3 
/ 9.5 TONS 


TANK NO. 2 
14.0 TONS 


TANK NO. 1 \ 
9.5 TONS \ 



-\ 


FIXED CONCRETE BALLAST 29 TONS 


ENTRY SKIRT 
6.0 TONS 


FIXED LEAD BALLAST 31 TONS | 





Fig. 46. Sealab II fixed and variable ballast 



80 DESIGN, CONSTRUCTION, AND OUTFITTING 

The deck is made of poured concrete two feet in depth and comprises a portion of the per- 
manent ballast. The deck and overhead ballast tanks reduce the usuable internal volume and 
consequently the amount of helium needed to fill the atmosphere, an important economic con- 
sideration (Fig. 47). 

This usable internal volume, 7 ft in height, is divided into four separate areas (Fig. 48). 
The aftermost area is the entry and contains two tub-showers to aid in regaining body heat 
after a sortie in 50°F water, as well as stowage for wet-suits and breathing apparatus. 

The next area forward is the laboratory, separated from the entry by a 3-1/2-ft watertight 
dutch door which gives an extra margin of safety if the water level should rise in the entry 
trunk into Sealab itself. The laboratory contains counter and stowage space, a sink, a cable 
trunk, instrumentation racks, the communications center, and the fan room, heart of the venti- 
lation system. 

Next forward is the galley area, containing stowage and counter space, an electric range, 
a refrigerator -freezer, wash basin and water closet, and the main power transformer enclosure 
and distribution panels. 

Finally, forward most is the berthing area with ten bunks, a dropleaf table, locker and 
stowage space. Access to the emergency exit hatch is through a removable cover in the deck. 

Mechanical/Electrical 

Ventilation System-The system consists of a central fan room with a 250 cfm capacity, 
recirculating centrifugal fan, discharging through ducting to the berthing, galley, laboratory, 
and entry areas. Return atmosphere is drawn into the fan room as follows: 

60 cfm directly through a LiOH CO2 scrubber, with the remaining 190 cfm by-passing the 
scrubber through a duct in the water closet bulkhead. The combined 250 cfm is passed through 
an activated charcoal filter, where noxious hydrocarbons are removed, and thence to the fan 
inlet. Bracket fans are utilized to aid circulation. The pitch on the fan blades and the impeller 
configuration are modified to allow for the increased density of the atmosphere as well as its 
increased pressure. 

Atmosphere Control -The atmosphere in Sealab II is comprised of 80% He, 15% Nj and 5% O2 
by volume at the proper pressure, i.e., hydrostatic pressure at the depth of the air -atmosphere 
interface. Initial pressurization is at the surface and consists of two parts, initially with air 
to give approximately the proper amount of O2 and then with helium to reach final pressure 
and mixture composition. Care must be taken to avoid overpressurization of the internal bal- 
last tanks. They must either be properly equalized or completely filled with water. 

There are two gas lines in the umbilical cord, a gas supply line to provide make-up helium 
and a gas sampling line to provide continuous atmosphere monitoring for analysis and also to 
provide an alternate means of oxygen make-up. 

Primary oxygen and helium make-up are from the gas bottles stowed externally. The 
oxygen bottles are manifolded dually to a pressure regulator inside Sealab which automatically 
replenishes oxygen to the atmosphere, responding to a specially designed sensor (Krasberg). 
The helium bottles are piped into a manual regulator. All gas supply, make-up, and sampling 
valves and fittings are centrally located inside Sealab n on a single gas control panel. 

Three external bottles are filled with a premixed supply of 95% He and 5% O2 piped into a 
regulator on the gas control panel which supplies eight, four outlet manifolds to which standard 
Scuba regulator -mouthpiece units can be plugged. This comprises the emergency breathing 
system, (Bibb System), and is used in case of severe atmosphere contamination. 

In the overhead of the entry area four supply compressors and four vacuum pumps are 
installed. Their function is to supply Sealab atmosphere through an external hose to the breath- 
ing gear of a swimmer on sortie and return exhaled gases back to Sealab. This is called an 



DESIGN, CONSTRUCTION, AND OUTFITTING 



81 




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DESIGN, CONSTRUCTION, AND OUTFITTING 83 

Arawak or "hookah" system and is very desirable for short sorties in that it frees the swim- 
mer from cumbersome scuba devices. 

Atmosphere Treatment— In addition to the control of CO 2 and hydrocarbon content, means 
are provided to regulate the temperature and humidity of the Sealab atmosphere. 

There are thermostatically controlled baseboard convection heaters in each area except 
the entry. Radiant heaters are provided in the entry area, nonthermostatically controlled. 
Imbedded in the concrete deck is a mineral insulated (MI) electric cable, with its own independ- 
ent thermostat control. The maximum total heating load is 25 KW. Normal design tempera- 
ture is 88°F. 

Eight commercial dehumidifier units are installed, each with a capacity of 47 pints/day to 
keep the relative humidity at 60 percent. Each is controlled by a humidistat. 

The increased heat transfer characteristics of the helium atmosphere require two inches 
of standard submarine cork insulation on the hull and one inch on the overhead. 

Direct reading and remote transmitting temperature and humidity sensors are installed. 

Fresh Water and Plumbing Systems — A boosted fresh water supply consisting of two one- 
inch PVC pipes laid from the shore to Sealab n is the primary source of fresh water. Demand 
is based on a maximum usage of 10 gal/min at 50 psig. In addition, a line from Sealab n to 
the staging vessel on the surface provides a means for topping off the staging vessel tanks 
during periods of low Sealab usage. 

An emergency fresh water tank is installed with a 150-gallon capacity in the overhead of 
the laboratory area. Also in the laboratory is a 50-gallon hot water tank with a short recovery 
time. 

The plumbing system consists of one small boat-type water closet, two tub showers, a 
washbasin and two sinks, one in the galley and one in the laboratory. 

Drainage is designed to be aft towards the entry area where a sump and overboard con- 
nection are installed. Hoses are installed externally to carry the drains away from Sealab. 
The water closet has its own salt water flushing and overboard discharge connections. 

Electric Power Distribution — Primary power is led to Sealab n via an underwater 2300- 
440 V transformer from the La Jolla power system. A 300-ft cable carries 440 v, three-phase 
60-cycle power into Sealab designed for a maximum of 75 kva. Alternate power is available 
via a cable in the umbilical. This is also 440 v, three phase, 60 cycle. 

The 440-v supply is used directly for the hot water, baseboard, and deck heaters. 400- 
120-v and 440 -208-v transformers handle the remainder of the loads. Standard protective dis- 
tribution panels, circuit breakers and switches are utilized. 

A transfer panel enables transfer from normal to alternate power. 

The Umbilical — The services from the staging vessel are brought down hoses and cables 
nested in what has become known as the "umbilical." Secondary power via a three -conductor 
cable, a multichannel communication cable, a gas-supply hose, a gas-sampling hose, and a 
compressed-air hose for external tool use make up the umbilical. The Sealab terminations 
for these lines are centrally located at the conning tower. The lines are brought together and 
lashed in a canvas jacket every few feet to form a nest. The staging vessel terminations are 
hooked up prior to lowering Sealab. 

Communications Via Umbilical — There is a helium speech unscrambler on the staging 
vessel modulating and converting the helium distorted speech of the subjects and is fed via one 
channel with transmitting stations in the laboratory, galley, and berthing spaces in Sealab n. 
A two-way electrowriter is also installed between Sealab and the staging vessel. Four TV 
cameras mounted in Sealab n transmit their output to monitors on the staging vessel. In 



84 DESIGN, CONSTRUCTION, AND OUTFITTING 

addition a TV receiver for entertainment as well as closed circuit monitoring is provided in 
Sealab. A two-way intercom system is available in the laboratory to the staging vessel. There 
it may be patched into the helium unscrambler. Another two-way intercom channel is alloted 
but this passes through Sealab for further transmission to shore. An FM entertainment re- 
ceiver, a wedge spirometer output (measuring subject respiration remotely), and O2 partial 
pressure sensing comprise the remainder of the channels in the communications link in the 
Umbilical. 

Communications Via the Benthic Laboratory — Scrlpps Institute has developed an underwater 
multichannel data transmission station, called the "benthic laboratory" which is situated on the 
bottom close to Sealab IT, A trunk is provided in Sealab aft on the portside of the laboratory 
which can be opened and through which cables can be passed. These cables then can run to and 
from benthic to provide the link with a shore based benthic control station. The link is audio, 
visual (TV), and digital and analog data transmission. 

Buoyancy and Stability 

The following tables should illustrate the various conditions of buoyancy and displacement. 
Refer to Fig. 43. 

Structure weight (less ballast, including outfit) 

Fixed Concrete Ballast 

Fixed Lead Ballast 

Variable 

Surface Displacement = Total Weight 

Submerged Displacement (defined as volume 
of conning tower, main cylinder, 
entrance skirt, and appendages): 

Ballast Tank 1 

Ballast Tank 2 

Ballast Tank 3 

Conning Tower 

Total Water Ballast 

Entrance Skirt 



119 tons 


29 tons 


31 tons 


5 tons 


184 tons 



Condition I Surface displacement 

1' 8" freeboard 
Flood tanks 1 and 3 

Condition n Sealab n floating at 

mid-height of conning 
tower 





209 tons 




9.5 tons 




14.0 tons 




9.5 tons 




11.0 tons 




44.0 tons 




6.0 tons 


iperations 


is as follows: 


Weight 


Net 

Buoyancy 

Tons 


184 tons 


■t-25 tons 


+ 19 tons 




203 tons 


+6 tons 



DESIGN, CONSTRUCTION, AND OUTFITTING 



85 



Condition n 



Condition in 



Condition IV 



Condition V 
Stability at each Condition: 







Net 






Buoyancy 




Weight 


Tons 


Sealab n pressurized 




with helium (tank 2 






and main cylinder) 






Flood conning tower 


4-11 tons 




Sealab during lowering 


214 tons 


-5 tons 


operation 






Set Sealab on ocean floor 






Flood tank 2 


f 14 tons 




Sealab on ocean floor, 


228 tons 


19 tons 


tank 2 flooded 






Blow entry trunk 


-6 tons 




Sealab ready for entry 


222 tons 


-13 tons 



Condition 




I 


GM = 2.29 ft 


n 


GM = 1.87 ft 


in 


BG = 2.21 ft 



BG at Condition m included the effect of the lowering whip as buoyant force. Conditions IV and 
V are on the bottom and bottom reaction would increase stability. Curves of forms, though 
academic, were prepared. 



CONCLUSIONS AND RECOMMENDATIONS 

It becomes very apparent in retrospect that a remarkable experiment, Sealab n, was suc- 
cessfully conducted in spite of several salient facts. Severe time and schedule limitations 
coupled with a very close budget precluded orderly progression and thorough investigation of 
many important engineering areas germane to underwater habitat design. Nonetheless, though 
lacking perfection of design in several areas, Sealab II functioned well as a habitat for three 
10-man teams for 45 days at 205 ft. It supported life safely and relatively comfortably. 

Experience gained in the progress of the design, construction, and outfitting of Sealab H 
as well as in its operation and overall project organization, will aid immeasurably in further 
man-in-the-sea operations. This has been just a whistle stop on our excursion down the con- 
tinental shelves. 

For the record, several conclusions can be drawn and recommendations made from the 
vantage point of the author. These reflect his opinions and analysis and may or may not be 
included in the official summary report of the project. 

1. A Naval Shipyard can be expected to respond to and undertake a project of this nature 
and deliver hardware on time and at a competitive cost. The Navy does have an in-house capa- 
bility for underwater habitat design and construction. 

2. A significant contribution to the technology of metal forming was made in the develop- 
ment and perfection of the technique of underwater explosive forming of large steel sections. 



86 DESIGN, CONSTRUCTION, AND OUTFITTING 

3. Engineering studies in the following areas must be undertaken at once: 

a. Atmosphere treatment to insure comfort and safety. Phychrometric charts for an 
He-02 atmosphere must be developed, and adequate dehumidification devices must be designed. 

b. An integrated gas supply and ballast control system to allow controlled descent and 
pressurization from within, much as a submarine statically dives. Once perfected, this would 
preclude heavy pressure structures. 

4. The interior arrangment of future habitats must be developed from the standpoint of 
human engineering, wherein careful functional analyses are made. In particular, attention 
must be given to the entry and diving -station area. 

5. A means for leveling the habitat is a necessity, since it became obvious a level site is 
very difficult to find. 

6. Communications and monitoring equipment must be improved. 

7. For succeeding man-in-the-sea operations, realistic schedules must be developed. 
Expedience must never be a substitute for quality. 

In conclusion, appreciation must be given to the fine people connected with the Sealab II 
project, and in particular the men and women of the Hunters Point Division of the San Fran- 
cisco Bay Naval Shipyard. All of them made Sealab II and this paper possible. 



chapter 12 
MODIFICATIONS AND OUTFITTING OF THE SEALAB II HABITAT 



W. B. Culpepper 

U. S. Navy Mine Defense Laboratory 

Panama City, Florida 

and 



E. P. Carpenter 
Naval Ordnance Laboratory 
Pasadena, California 



Originally, the Sealab II habitat was to have only final outfitting and trim tests performed 
while at Long Beach Naval Shipyard. However, due to schedule changes, design reevaluations, 
and the requirements of the Certification Board, a number of modifications were necessary 
(see Fig. 49 for valve locations). 

These modifications, with the reasons for their accomplishment, are listed below. 



I. Exterior Modifications 
Item 

1. Install guards at forward end of bottle- 
storage racks. 

2. Shorten external portion of water closet 
overboard drain line. 

3. Add expanded metal bin on starboard 

side. 

4. Install valve from vent valve B-3 to 
top of skirt. 

5. Remove protective cover from valve 
B-3. 

6. Install padeyes on top of shark cage. 

7. Add miscellaneous hooks inside skirt. 

8. Add vent valve A- 10. 



Reason 



Protect high-pressure piping and valves. 



Less vulnerable. 



Additional exterior storage. 



Blowing skirt; pressure equalization during 
tidal changes. 

Better access to valve handle. 



Attachment of dumbwaiter line. 

For handing equipment. 

Permit venting tank No. 4 while maintaining 
pressure equalization between other tanks 
and interior. 



n. Umbilical cord Modifications 

1. Replace air hose, gas-supply hose, and 
gas-sampling hose. 



Original hoses kinked and unusable. 



87 



MODIFICATIONS AND OUTFITTING 




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MODIFICATIONS AND OUTFITTING 



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Item 



2. Add three cables. 



3. Marry umbilical components at 8 ft 
intervals with 9 -thread manila. 



Reason 

Two for external lights, one for camera 
control 

Ease of handling. 



m. Interior Modifications 

1. Remove chain stanchions and deck 
sockets at entryway. 

2. Shorten vent duct and move radiant 
heater in entryway. 

3. Add sound-absorbing curtains between 
entry and laboratory space. 

4. Remove electrical convenience outlets 
in entryway. 

5. Install copper tubing from waterheater 
relief valve to deck drain. 

6. Install pressure-relief valves on O2 
and Bibb system with overboard dis- 
charge through benthic trunk. 

7. Install flow meter in Oj make-up line. 

8. Install valves H-8 and H-9 in O 2 
make-up system. 

9. Add U-tube monometer on suction side 
of vent blower. 

10. Install screen on CO 2 scrubber. 

11. Install additional shelving in berthing 
and galley spaces. 

12. Relocate helium speech unscrambler 
plug receptacle in galley. 

13. Modify doors and screws on electrical 
distribution panels. 

14. Move washbasin away from hull. 

15. Install two 220-cu ft O2 cylinders. 

16. Remove thresholds between berthing 
and galley spaces. 



Ease of entry. 

Provide space to install hookah compressors. 

Improve communications while operating 
hookah. 

Damp entryway could cause shorting. 
Safety-required by Certification Board. 
Safety-required by Certification Board. 

Safety-required by Certification Board. 

Allows bleeding into lab if vent blower be- 
comes inoperative. 

Determines when filter needs charging. 

Protects CO 2 scrubber filter. 
Additional storage space. 



Avoid interference with circuit breaker 
door. 

Permit complete closing of doors. 



Provide adequate head room. 

Provide supply for manual O2 make-up. 



During the same period in which the above modifications were being accomplished, final 
outfitting was completed. Major items accomplished during this outfitting period are listed 
below: 



90 MODIFICATIONS AND OUTFITTING 

I. Exterior 

1. Secure gas bottles in racks with wooden wedges. 

2. Install freshwater manifold and pressure regulator in Sealab/Staging Vessel freshwater 
system. 

3. Attach human-engineering test platform to after end of shark cage. 

4. Install BT winch mount on shark cage. 

5. Install racks for ten 38-cu-ft emergency scuba bottles. 

n. Interior 

1. Install shower curtain rod. 

2. Install hookah compressors. 

3. Install self-coiling hoses on all Bibb system outlets. 

4. Install carpet on deck. 

5. Install heated-suit power pack in laboratory space. 

6. Install event recorder in laboratory space. 

7. Install Krasberg POj sensing and monitoring unit on vent-system compartment. 

8. Install electric timers for human-engineering tests beneath patch panel. 

9. Install hanging rod behind refrigerator-freezer for stowage of charcoal filters. 

10. Install light banks, filter, and plant-box racks in water-closet space. 

11. Install FM speakers overhead in berthing space. 

12. Clean and pressure test all gas systems. 

13. Install TV camera mount aft of main access. 

14. Install electrowriter transceiver. 

15. Install wedge spirometer. 

When it was determined that all modifications were complete, a complete systems check 
was performed. Sealab II was sealed and pressurized to 5 psi above atmospheric pressure. All 
electrical and gas systems were checked for proper operation. Sealab n was then placed in the 
water for trim tests and cycling of the flood and vent system. 

With all preparations complete, the habitat was towed to the site near La JoUa. 



Chapter 13 
SEALAB II EXTERIOR LIGHTING 

R. A. Barth and P. A. Wells 

U. S. Navy Mine Defense Laboratory 

Panama City, Florida 

INTRODUCTION 

The exterior lighting provided for Sealab II was Standard Navy diving lights, Symbol 313, 
as shown in BuShips Drawing 9000, S6405-74445, mounted on the exterior of the hull. As con- 
structed by San Francisco Naval Shipyard, the power cables and plugs were to be led in through 
a section of the instrumentation trunk, connected to an interlocking switch and receptacle direc- 
tly above the instrumentation trunk. A switch and receptacle was provided for each light. Dur- 
ing the outfitting by Naval Ordnance Test Station at Long Beach, a decision was made to alter 
this arrangement by using Electro-Oceanic underwater connectors. The underwater connectors 
as well as the locations of the lights were numbered 1 through 6 for identification. Considera- 
tion was given to the use of the Burns -Sawyer Underwater Lights; however, the reports from 
Sealab I indicated that more problems were experienced with these lights than with the Navy 
diving lights. An oversight in selecting the Navy diving lights was in their short life, 50 hours 
nominal. The experience of Sealab II, however, indicates that the life is much longer. 

After failure of the Navy diving lights on Sealab II, other types, such as quartz iodine and 
mercury vapor were used with varying degrees of success. From all reports, it seems that the 
primary failure of the quartz iodine light was due to the housing. Quartz lamps are very rugged 
to thermal shock and are small in size and produce about 21 to 22 lumens per watt. They can 
be operated on standard voltages and require no auxiliary equipment. The mercury vapor lamp, 
like any discharge lamp, requires that some sort of current-limiting device be used. Ballasts 
are used to limit the current and act as transformers to provide sufficient voltage for starting 
and operating. This voltage may be as high as 460 volts. The efficiency of the mercury vapor 
lamp is very high; the lumen-per-watt output ranges from 23 for the 100 watt size to 54 for the 
1000 watt size. The mercury lamp produces a bluish-white light which is not suitable for photo- 
graphy.. 

It would appear there is a need for improved underwater lighting. The writer suggests 
that the following factors be considered in the development of improved underwater lighting. 

1. Diver safety, i.e., low operating voltage or good insulation 

2. Long life 

3. Efficiency 

4. Simple lamp replacement 

5. Light and portable 

6. Suitability for photography 



91 



92 EXTERIOR LIGHTING 

EVALUATION OF DIVING LIGHTS, TEAM I 

1. There were six diving lights on the Sealab II habitat - one on each end and two on each 
side. The lights were 1000-watt incandescent bulb type. The plugs were Electro-Oceanics 
types which were plugged in underwater. These plugs gave no trouble. 

2. The amount of light from each bulb was sufficient; also the number of bulbs. The lights 
were necessary during the day due to the darkness of the water at Sealab n depth. The maximum 
range observed was 80 to 90 ft. 

3. The first diving light failure was noted on day 5. The time required to fix this light, 
splicing in a new bulb, was about one hour. By day 15, all of the lights except one had failed. 

4. Conclusions: The bulbs provided sufficient light but were of short duration. Too much 
time is consumed in changing the bulbs. A better way of changing the bulbs is definitely needed, 
with screw-in or bayonet type preferred. A longer life bulb is desirable. 

EVALUATION OF DIVING LIGHTS, TEAM E 

1. Three types of lights were used during Team 2's stay on the bottom: 

a. The standard Navy diving lights that were mounted at various locations outside. 

b. The Burns-Sawyer type light. This was a portable light utilized mainly around the 
shark cage area. 

c. The mercury-vapor light that was manufactured by "Oceanics." 

2. During Sealab I the standard Navy diving light and the Burns-Sawyer light were both 
used and, of the two, the Navy diving light proved to be more trustworthy, although it required 
bulb replacement quite frequently, a task always long and seemingly not worth the effort. The 
Burns-Sawyer types gave very limited service and were eventually abandoned because of their 
constant failure. 

3. During Team 2's stay in Sealab 11, both these lights were used, and with about the same 
results as that of Sealab I. The Burns-Sawyer lights were more or less abandoned for the same 
reason as in Sealab I. The standard Navy diving light required very frequent bulb changing; 
this was generally a half-day job which usually involved two or more lights. Very seldom were 
all these lights in operation. Two divers could have kept themselves busy for the complete 15- 
day stay just going through the sequence of bulb replacement. 

4. The mercury-vapor light was introduced to Team 2 during our stay. Although a power 
pack was required to operate this light, it proved to be very superior to anything that most of 
us had ever witnessed. The brilliancy of this light was outstanding. Compared to the other two 
types, it was many times brighter and gave us practically "sunshine brightness" when mounted 
above the shark cage and used to illuminate the inside of same. To my recollection, very little 
maintenance was required, and even then only a short time was involved. 

5. A very limited amount of experience was actually obtained by Team 2 on the mercury- 
vapor light, since only one was available. What little experience that was had with this light 
proved its high potential. Its brilliancy is what is necessary for this type of work in the waters 
where it will be used. 

EVALUATION OF DIVING LIGHTS, TEAM IH 

1. First day: Upon arrival of team, two lights were burning. One was mercury-vapor type 
which requires a separate power pack inside the lab in addition to the 110-v ac source. This 
bulb may be replaced in the water. The second light burning was the standard USN 1000-watt 
diving light, which burned out on the second day. With no replacement bulbs, no further work 



EXTERIOR LIGHTING 93 

with the USN diving lights occurred until the 14th day when all lights were made up and stowed 
in the cage on the starboard side. 

2. a. An underwater harness had been made up for disconnecting the USN lights outside 
the habitat, but no record had been kept so no one knew which light was connected to which 
underwater connection. We had to turn off all lights when removing or replacing or repairing 
bulbs. 

b. The USN 1000-watt light lasted on the average of 36 hours. It is known that turning 
on and off both types of lights shortens the life of the bulb considerably. 

3. Team 3 used three mercury lights during its stay, burning out three bulbs each and one 
power pack. These lights were very good, but usually they burned out when they were turned 
off and then on, even in the water. 

4. The power pack which burned out in the lab was disconnected when the odor of something 
burning was detected. A short was subsequently discovered in the underwater connection plug. 

5. The Burns and Sawyer photo lights were connected with the switch topside, but this was 

a poor arrangement, since two separate divers received electrical shocks when recovering them 
to be sent topside for repair after burn-out. There was a slight crack in the lens of each one. 
These lights were the quartz type. 

6. General Comments. 

a. USN Diving Lights: 

(1) The mix-up in the lights occurred as a result of making them up prior to lower- 
ing and not tagging in several places. Recommend: Sealab divers install and connect own lights 
and keep a log of same. 

(2) Get a longer-life bulb. 

(3) Recommend: An easy underwater bulb-replacement procedure. 

(4) Recommend: Mercury-vapor type lights. 

b. Mercury-vapor type: 

(1) Need an easier underwater connector. The one used required two men to dis- 
connect and had two-prong poles, one just a little smaller than the other. This required bring- 
ing inside the lab to connect up. 

c. Burns and Sawyer Diving Lights: 

(1) Install switch inside the lab. 

(2) Eliminate the electrical hazard of cracked lens. 



chapter 14 
ARAWAK SYSTEM ON SEALAB 



B. Deleman, B. Cannon, W. T. Jenkins, and P. A. Wells 

U. S. Navy Mine Defense Laboratory 
Panama City, Florida 



INTRODUCTION 



The Arawak system for divers was purchased on contract from Westinghouse Electric 
Corporation of Baltimore, Maryland. Equipment delivered consisted of four motors, four 
pumps, and two sets of breathing-gas hoses (100 ft each), with vests and demand regulators. 

At Long Beach Naval Shipyard, the equipment was dismantled and installed on a common 
base above the entry hatch. Minor modifications were made prior to installation. Gate values 
were procured and installed in the supply and return systems to cross-connect all units, so 
that one set of hoses would always be ready for use. 

After completion of installation all units were checked out and tested. Results were sat- 
isfactory, but the units were very noisy. The time element prevented elimination of some of 
the noise problems common to these pumps and compressors. Space limitations also restrict- 
ed the installation design. 

ARAWAK EVALUATION, TEAM 1 

General 

No specific record of Arawak time was kept while Team 1 was in Sealab, except in the 
ship's log. Therefore, only an estimate of the time used can be made at this time. Of the to- 
tal period spent outside the habitat, divers employed the Arawak system about 50 percent of 
the time. Since the major portion of Team I's initial tasks concerned the habitat or immedi- 
ate vicinity, the Arawak was used considerably the first nine days. It is ideally suited to this 
situation. 

Advantages and Disadvantages 

The major advantages of the Arawak are (a) lack of predive preparation, and (b) unlimited 
gas duration. The units were very reliable, with the only malfunction being a stuck vane on 
No. 2 vacuum pump. This pump was repaired on the bottom satisfactorily. 

The hoses were a nuisance, getting tangled and twisted every couple of days. The vest de- 
sign needs improvement, especially in the way the hoses attach. There is a tendency due to 
the weight of the hoses to pull the vest open. The regulator is too close under the chin and 
must be disconnected to get out of the vest. The range was about 80 ft horizontal and 30 ft 
up or down. At times kinks developed, causing extremely hard inhalation or exhalation. 

Operation 

The Arawaks were used extensively for pot handling, PTC work, and removal of the outer 
port covers. They were easy to breathe in, and, since the two vacuum and two pressure pumps 

94 



ARAWAK SYSTEM 95 

were paralleled, supplied plenty of gas. The vests were awkward to get into, and a tender 
was definitely needed. 

Recommendations 

Smaller, neutrally buoyant (or slightly negative) hoses would be helpful, and the vest needs 
some redesign. The regulator should not be so close under the chin, since ditching the rig 
would be virtually impossible. The pumps were very noisy and need some sort of acoustical 
shielding inside the Sealab. 

ARAWAK EVALUATION, TEAM 2 

General 

During the 13 diving days that the members of Team 2 were in Sealab 11, the two Arawaks 
were used a total of 36 hours, or slightly more than 1/3 of the total diving time of some 98 
hours 50 minutes. Individual use of the rigs varied widely from man to man, with ranges of 
5 to 70 percent of total diving time being Arawak. Every aquanaut used these rigs from a low 
of 18 minutes total to 10 hours 14 minutes total, with an average use of 3 hours 36 minutes 
per man. 

Initially the Arawaks were used as a secondary or 'iDack-up" system to the Mark VI, but 
more and more emphasis was placed on them each day. Most Arawak dives were very local, 
being used for pot transfer and general maintenance work on or in immediate vicinity of the 
habitat. No Arawak dives were made to distances greater than 50 ft. from the habitat due to 
hose limitation. 

Advantages and Disadvantages 

Advantages of the Arawak included the ease and rapidity with which it could be made ready 
for use. The unlimited gas supply and the safety of being tethered to the habitat gave the aqua- 
nauts an additional feeling of security which was not felt using the Mark VI. The time and ef- 
fort necessary for setting up a Mark VI for a dive was an additional strain on the aquanauts; 
the Arawak was a welcome relief from this. 

Disadvantages were incurred using the two Arawaks, the most prominent of which was the 
noise inside the diving- staging area while the pumps were running. This noise, plus the dis- 
torted voices, made conversation nearly impossible in this area. In addition, the buoyant hose 
had a tendency to pull the aquanaut up and back as he swam out from the habitat. This hose 
tended to kink and also tended to snag on the transfer pots, which made it unsafe to use during 
pot transfer. The limited range in which a diver using the Arawak could operate was the most 
important factor governing their use. 

Recommendations 

Improvements should include a baffle system so the pumps could be run and not interfere 
with conversation. Hoses should be neutrally buoyant so they won't kink; and a safe, quick- 
release system should be incorporated into the harness. The quick release is necessary due 
to the chance that a diver, in an emergency, would have his hose snag while swimming back to 
the habitat. 

ARAWAK EVALUATION, TEAM 3 
General 

Use of the Arawak varied from at least one dive for all members to 12 dives for one 
member. Team average was three dives. The Arawak was used a total of 84 hours. 



96 TUIAWAK SYSTEM 

The method of operation was to run both pumps connected together via a 1-in. I. D. mani- 
fold. No one performed work with a single vacuum and pressure pump running; therefore, all 
comments refer to the system with both pumps running. 

Condition of the equipment at the start of the Team 3's dive: pressure pump gauges read 
20 psi vs 24 psi; vacuum-pump gauges read 14.5 psi; one vest was completely beyond use, i.e., 
no zipper, and regulator would not exhaust. 

General Comments by Team Members 
Advantages 

1. Liked the weight arrangements in the vest. 

2. Three team members liked the positively buoyant hoses. 

3. Some heating was obtained from the warm gas pumped from the habitat, i.e., when 
using the Arawak, divers felt warm. 

4. Could not overwork the rigs with both pumps running. 

5. No pump maintenance was required by Team 3. 

Disadvantages 

1. Did not like the position of the regulators. The position could not be adjusted for the 
varying heights of the users. 

2. Hard to exhaust. 

3. The pumps were too noisy. Voice communication was impossible when the pumps 
were running. 

4. Seven members thought the hoses would have been less easily tangled if they had been 
slightly negatively buoyant. 

5. All felt that they could not get out of the rig quickly in an emergency. 

Summary 

All members realized the importance of the Arawak for future deeper dives in Sealab-type 
operations and therefore were very interested in it, even though all preferred free diving. If 
safe diving techniques were employed, all members felt the Arawak was a safe rig as designed. 



Chapter 15 
HANDLING CHARACTERISTICS OF SEALAB II 

T. N. Blockwick 
Boston Naval Shipyard 
Boston, Massachusetts 

and 
E. P. Carpenter 
Naval Ordnaupe Test Station 
Pasadena, California 

INTRODUCTION 

During construction of Sealab II, eight lifting padeyes were provided. Four of these eight 
were used whenever Sealab was moved by lifting. Cranes capable of lifting the 200-ton habitat 
completely out of the water were available in San Francisco and Long Beach. For towing, a 
closed chock was provided on both the bow and stern. 

The primary restriction imposed on all handling operations was that at no time could the 
habitat be allowed to come in contact with any dock or floating vessel. This restriction was 
imposed bacause of the vulnerability of its many exposed fittings, valves, and external gas- 
storage bottles. 

HANDLING OPERATIONS 

Sealab n was transported from the construction site. Hunter's Point Division, San Fran- 
cisco Bay Naval Shipyard, to Long Beach Naval Shipyard by barge towed by USNS Gear. At 
Long Beach, the habitat was placed in the water and towed to the site near La JoUa by USNS 
Gear. This tow was an event with many unknowns, because the hull of Sealab was not designed 
for towing. Only the conning tower and 1 ft 8 in. of the main cylinder were above the surface. 
Most of Sealab was under water. Most of the stores and equipment were loaded at Long Beach. 
It was planned that only last-minute items would be loaded at the site. 

The most important procedures for preparing Sealab for surface towing was putting on in- 
ternal and external port covers, placing internal strongbacks on the main access hatch, and the 
emergency escape hatch. All hatches were closed, and Sealab was pressurized to 20 psi gage. 
A light alarm was rigged to indicate loss of pressure. If the pressure dropped to 16 psi, the 
light would be actuated. 

The tow was rigged from one of the forward lifting pads through the bow bull-nose chock. 
Starting from the lifting pad, the tow was arranged, as follows: pelican hook, 1-1/2-in. chain 
through bull nose, about 150 ft of 1-5/8-in. wire that was attached to the main 2-in. towing wire 
of the GEAR (ARS-34). 

The distance from Long Beach to the Sealab 11 site at La JoUa was 80 naut mi, and 36 hours 
was allowed for transit. This time would give an average speed of slightly more than two knots. 
However, Sealab towed better than anticipated, and it arrived at the site early. The scope of 
wire used by the Gear (ARS-34) was only from 100 to 300 ft. The normal minimum of 1200 ft 
could not be used, since the weight of the 2-in. tow wire could probably cause the Sealab to 
plunge. After arrival of Sealab at the site, it was moored to the No. 2 mooring spud until it was 
ready for lowering. 

97 



98 



HANDLING CHARACTERISTICS 



Preparations for submergence included a complete systems checkout (see Sealab n Lower- 
ing Plan, this chapter), the final loading of supplies and equipment for the aquanauts, and the 
flooding of ballast tanks 1 and 3. When tanks 1 and 3 were flooded, the waterline was on the 
conning tower at a point which indicated that, when the conning tower was flooded, Sealab would 
be approximately 10,000 pounds negatively buoyant. 

The Sealab was then placed in a four-point moor between the Gear and the stern of the sur- 
face support craft (Fig. 50). Prior to this, the Gear was placed in a three-point moor parallel 
to the stern of the surface support craft about 100 yd away, so it could assist in the lowering of 
Sealab. 




NYLON 



Fig. 50. Sealab attitude from surface to 30 feet depth (also 

see Fig. 66) 



The actual lowering was done from a boom that extended only ten feet from the surface - 
support craft. Thus, the Sealab habitat had to remain about 30 ft clear until it was well 
submerged. 

The lowering wire was 1-1/8-in. nonrotating and was connected to a winch. To absorb the 
dynamic loads of Sealab due to wave and swell action of four to six feet, the lowering wire had 
a counterweight of 13,000-lb, which was controlled by the second winch on the surface craft. 



When all was ready, the flooding of the conning tower was started, and a mixture of helium 
and oxygen gas was maintained at 30 to 40 lb over ambient water pressure inside the Sealab. 
When Sealab became slightly negative, it submerged gently and rotated down to a depth of about 



HANDLING CHARACTERISTICS 99 

60 ft. At this point, a short stop was made to disconnect excess lines and to inspect it for leaks. 
Some of the ports developed gas leaks. To minimize gas loss, the Sealab was lowered to the 
bottom as soon as possible. 

When Sealab landed, instrumentation indicated that it had a 10-degree trim by the stern and 
a list to port of three degrees. It was then lifted about ten feet off the bottom and rotated to 
another position. It ended up with a list to port of six degrees and a trim by the stern of also 
six degrees. No. 2 tank was then flooded, and Sealab was hard on the bottom. 

The counterweight system on the lowering tackle performed extremely well, and readily 
absorbed shock loads imposed by the swells and the movement of the Berkone. The Dynaline 
Tensiometer, which measured the tension in the lowering wire at all times, showed maximum 
loads of about 25 percent over the negative weight of Sealab II, which was 9500 lb. 

Sealab was then ready for occupancy. The following day, on Aug. 28, the first ten aquanauts 
entered Sealab to begin their existence in 205 ft of water. 

Shortly after Aquanaut Team 3 surfaced on Oct. 10, preparations were begun to raise Sealab 
to the surface. The items shown in Phase I of the raising plan were accomplished by Team 3 
prior to their surfacing. The same day, most of the preparations to be made by surface divers 
were carried out, with the exception of blowing ballast tank 2. 

On Oct. 11, the Gear was placed in a four-point moor in a position to control Sealab as it 
started to surface. Refer to the Sealab n Raising Plan, Phase II. 

Then tank 2 was blown, and a strain was taken on the lifting wire and the counterweight 
system, to pull the spades of Sealab out of the soil. From the original six-degree port list and 
six-degree trim by the stern, both of these values reduced to about three degrees. However, 
despite 20,000 to 25,000 lb pull, Sealab II would not raise. Additional pulls were also taken by 
the Gear and Berkone at the stern, and bow chocks with 3-1/2-in. nylon, but Sealab apparently 
was too heavy. 

It was decided to add a 3000-lb anchor to the 13,500-lb counterweight to reduce chafing of 
the wire under heavy strain. A dive was made to blow tank 2 clean and to blow tank 1 for three 
minutes and tank 3 for two minutes. This procedure reduced the load somewhat, to about 
17,000 lb. Three of the porthole plugs were also capped to minimize gas loss. Later, another 
dive was made to blow tank 2 clean and tank 3 for three minutes. This raised the bow and re- 
duced the tension in the cable to about 15,000 lb. Sealab was raised to 65 ft, and six-inch lines 
were run, as shown in the Raising Plan. At 1500, Oct. 11, Sealab was brought to the surface, 
after the conning tower was blown. She remained in this position overnight, with 33.5 psi ab- 
solute being maintained. On Oct. 12, the pressure was reduced via the umbilical and opening 
of valve B-3. To expedite this, the conning tower was pressurized to open the hatch leading 
from the conning tower to the Sealab. However, when this was done and Sealab opened to the 
atmosphere, it began to take in water, apparently through the ballast-tank equalizing system. 
The Sealab was then quickly repressurized to 25 psi. It was decided to take her back to Long 
Beach as it was, without opening Sealab on the surface. The primary reason for opening up 
Sealab was to install the interior strongback over the large access hatch. After the water was 
blown out of it, Sealab was repressurized to 25 psi. The low-pressure light indicator was set 
to 10 psi. In addition, a pressure gage was provided on Sealab. Facilities were provided so 
that air could be supplied by the Gear while under tow. Four Sealab II divers rode the Gear to 
assist in the event of an emergency. Sealab was taken in tow at about 1800, Oct. 12, 1965, and 
arrived at Long Beach at about 1400, Oct. 13, 1965. It was lifted out of the water shortly after 
arrival. 

The sea and weather conditions during both tows were good and essentially State 1. 

SEALAB II LOWERING PLAN 

Conditions : Sealab n outfitting is completed, and it is sitting out of the water at Long Beach 

Naval Shipyard. All stores and dry (nonfrozen) provisions are stowed aboard. See 
Figure 49 for location and function of valves. 



100 HANDLING CHARACTERISTICS 

1. Secure the internal pressure-proof covers onto the viewing ports and bolt down hard, 
using a diagonal bolting sequence. 

2. Remove the equalizing plugs on each viewing port from the outside. 

3. Open the equalizing plug and valve in the transformer enclosure and in the base of the 
water closet. 

4. Install the external protective covers on the viewing ports. 

5. Fill the 150-gallon emergency fresh-water tank. 

6. Open the faucet on the water heater and all other faucets on the fresh water system. 
DO NOT fill the water heater. 

7. Block the water-heater switch on the main power panel in the off position. 

8. Open the gas supply and gas-sampling valves Dl, D2, D3(2), E2, E3, and E5. 

9. Close the 48-in. -diameter hatch and bolt down tightly. 

10. Check the emergency escape hatch to be sure that it is properly secured. 

11. Install and bolt down tightly the strongbacks on the main and emergency access hatches. 

12. Secure all systems and switch off power. 

13. Vacate Sealab via the conning tower, close and secure the lower conning tower hatch. 

14. Close the upper conning-tower hatch and bolt down securely. 

15. Stow the normal power pigtail on top of the conning tower. 

16. Attach the atmosphere-gas-loss alarm to the end of the gas-sampling line of the umbil- 
ical cord. 

17. Remove the caps from all flood and vent valves. 

18. Open equalizing valves Bl and B2 and vent valves A2, A4, and A6 to equalize the pres- 
sure between ballast tanks 1,2, and 3 and the living compartment. 

19. Conduct a 15-psi pressure test and a 10-psi vacuum test on Sealab as outlined in 
NAVSHIPYD SFRAN Test Memo Mo. SLn-126T-147. 

20. During the pressure test, check that the atmosphere-gas alarm is working properly. 
Leave the alarm energized. 

21. Attach the German Crane lifting slings to Sealab. 

22. With the German Crane, lift and place Sealab in the water. Sealab should float with 1 ft 
8 in. of freeboard. Access can be gained through the conning-tower hatches. 

23. Conduct the necessary trim and buoyancy checks. 

24. Remove the lifting slings. 

25. Make the necessary towing connections. Towing will be done with the forward inboard 
pad. 

26. Install the lowering bridle to the lifting pads. 



HANDLING CHARACTERISTICS 101 

27. Recheck to insure that items 1 through 18 are still in force. 

28. Charge Sealab with air to 20 psig through the gas-supply line of the umbilical. 

29. Close valves Dl, D2, A2, A4, A6, Bl, and B2. The conning tower is not pressurized. 
(DO NOT tighten the nuts on the securing brackets of the main access hatch after charging.) 

30. Energize the towing lights. 

31. Tow to the site with Gear, following coastal shallow water. A Sealab II Officer will be 
on the Gear and will ascertain the correct towing speed. 

32. Upon arrival at the site, Gear will pass Sealab to an LCM and then place herself in a 
moor directly aft of the staging vessel. 

33. Kickers pass positioning lines from Sealab to the staging vessel and to the Gear (two 
lines to each) 

34. Connect the lowering line (slack) to the Sealab lowering bridle, rig the counterweight 
and connect the Dynaline Tensiometer. 

35. Open vent valves A2, A3, A4, A5, A6, A7, AlO, and equalizing valves Bl and B2. 

36. THEN open master vent valve Al to bleed out pressure inside of Sealab. 

37. Open upper and lower conning-tower hatches and enter. 

38. Close valves A2, A3, A4, A5, A6, A7, AlO, Bl, and B2. 

39. Close gas valves D3(2), E2, E3, and E5. 

40. Check the operation of positioning lights on the bottom. 

41. Remove all but two bolts from the external protective covers on the viewing ports, using 
surface divers. (Recheck to insure that the viewing port equalizing valves are open.) 

42. Flake out the umbilical onto the sea and attach intermediate floats. Connect the umbil- 
icla to the staging vessel. 

43. Connect the normal power pigtail to the shore power line. 

44. Switch on the alternate electrical power to Sealab from the staging vessel. 

45. Move the alternate power switch on the main power panel in Sealab to the on position. 
Switch on all circuits, except the water heater (it is empty) and spare circuits, in the main 
power panel. 

46. Switch on all circuits in the three power panels located adjacent to the main power panel 
in the galley area. 

47. Turn on all lights, heaters, dehumidifiers, ventilation, and the refrigerator. 

48. Check all systems to insure that they are working properly on alternate power. 

49. Switch on the normal power supply from shore. 

50. Move all switches on the main power panel to off. 

51. Move the normal power supply switch to on. 



102 HANDLING CHARACTERISTICS 

52. Move the remaining switches, one at a time to on. (Except the switches for the water 
heater, stove and radiant heaters in the entry.) 

53. Check all systems to insure that they are working properly on normal power. 

54. Using the same procedure, switch back to alternate power. Alternate power will be 
used during lowering. 

55. Lower the TV camera tripod to the bottom and check it out for proper operation. 

56. Complete the final loading of equipment into Sealab. 

57. Place the automatic oxygen system in a "service for use on the bottom" condition by 
opening the following valves in sequence: H9, H3, H2(2). Then energize the Krasberg oxygen 
sensor. 

58. Prepare to charge Sealab by opening internal valves D3(2), E3, and E4 or E5. 

59. Remove the strongback from the main access hatch. Stow it in Sealab. 

60. With all necessary systems operating on alternate power, vacate Sealab and secure the 
conning-tower access hatches. 

61. Take Sealab draft readings. 

62. Open vent valves A2, A3, A6, and A7 of ballast tanks 1 and 3. 

63. Open flood valves CI and C3 of ballast tanks 1 and 3. Then open vent valve AlO and 
master vent valve Al. Sealab, if properly ballasted, will submerge to approximately the 
9000-lb mark, near the mid-height of the conning tower. 

64. Close flood valves CI and C3 and vent valve Al and AlO when tanks 1 and 3 are com- 
pletely flooded. 

65. Take Sealab draft readings. 

66. Open the equalizing valves Bl and B2 and vent valves A4 and A5 of ballast tank 2. 

67. Open external valves Dl, D2, and E2 and charge Sealab through the gas- supply line of 
the umbilical cord to Sealab depth plus 5 psi. A pressure gage will be attached to the gas- 
sampling hose in the atmosphere control van to read out the pressure. The charging will be 
done as follows: (1) Charge to approximately 28 psi* with air. (2) Complete the charge with 
helium. 

68. Check for pressure in the conning tower by opening and closing C4. 

69. Take marks on the lowering wire. 

70. Inspect the complete counteiweight system to insure that it will function properly. 

71. Flood the conning tower by opening its vent valve A8 and its flood valve C4. Sealab will 
now completely submerge and will impose a tension load of approximately 9000 lb on the low- 
ering line. Leave valves Al, A8, arid C4 open to prevent any damage to the conning tower dur- 
ing lowering. 

72. Prepare to plumb Sealab on short stay as it becomes negative. 



*The exact pressure will be decided by the exact Sealab test depth. 



HANDLING CHARACTERISTICS 103 

73. When Sealab is in the plumb position, make all possible checks of lowering equipment. 
Take dynaline readings and make certain that the reading remains constant before starting the 
lowering. 

74. Lower Sealab to within approximately 20 ft of the bottom (within sight of the positioning 
lights). Make sure that the umbilical follows it down smoothly. 

75. Take another dynaline reading. It should agree with the reading taken in item 73. 

76. Position Sealab with the tag lines from Gear. The bow of Sealab should point at approxi- 
mately 345°T. The shark-cage end is the stern. 

77. When Sealab is correctly positioned, lower it to the bottom. When it is on the bottom, 
check to insure that it is reasonably level. 

78. Flood ballast tank 2 by closing equalizing valves Bl and B2, then opening flood valve 
C2, then opening vent valve AlO. 

79. Leave the bridle (slack) in place until everything is completely checked out. (This check- 
out will take at least 24 hours.) 

SEALAB RAISING PLAN 

Phase 1 

Conditions: The necessity for raising Sealab may arise at any time after Sealab is placed on 
the bottom. For this reason, it is not possible to state the exact condition of the 
many systems aboard. For the purpose of this bill it is assumed that Sealab has 
been on the bottom and occupied for a sufficient length of time that all systems are 
checked out and in operation on normal power. Also, ballast tanks 1, 2, 3 and the 
conning tower are flooded and the entry skirt is blown out. 

1. Lift up way-stations, water-clarity meter, acoustic ranges, and other equipment as 
necessary. 

2. Remove caps on the inside end of the equalizing plugs in the eleven viewing ports. 

3. Remove preventer anchor cable, attach to messenger, and send topside. Attach tag lines 
to prevent Sealab rotation. 

4. Secure the internal pressure-proof covers on the viewing ports and bolt down hard, 
using a diagonal bolting sequence. Use a torque wrench adjusted to not more than 100 ft-lb. 

5. Remove the equalizing plugs on the outside of the viewing ports. 

6. Remove all outside TV cameras (and mounting brackets). 

7. Install the external protective covers on the viewing ports if time permits. 

8. Connect an air salvage hose from the staging vessel to vent valve Al. The air salvage 
hose should have a check valve at the staging-vessel end, with a valve capable of venting pres- 
sure on Sealab as required. 

9. Block the water-heater switch on the main power panel in the off position. 

10. Disconnect the diving light cables and lash in place. 

11. Notify shore control to turn off Benthic power. When power-off confirmation is received 
from topside, proceed with item 12. 



104 HANDLING CHARACTERISTICS 

12. Remove all cables and pipes from the wiring trunk and stow them in their respective 
places. 

13. Ascertain that all cables are clear of Sealab. This is a continuing project. 

14. Install the cover on the wiring trunk and bolt down tightly (100 ft-lb). 

15. Remove the hoses from the outside plumbing drains, close the valves, and cap. Stow 
hoses in outside cage. 

16. Close the fresh water valves, disconnect the two fresh-water hoses from Sealab. In- 
form shore control when this is completed. 

17. Close the salt-water supply valve to the water closet and cap. 

18. Open the equalizing plug and valve in the transformer enclosure and in the base of the 
water closet. 

19. Move all switches on the main power panel to off position. 

20. Apply power to the umbilical power cord from the staging vessel. 

21. Move the alternate power supply switch to on. 

22. Notify shore control to secure shore power on the pier to the power beehive. 

23. Move the remaining switches, one at a time, to on. (except the water heater switch.) 

24. Install the inclinometer: plug into the FM Music and Electrowriter receptacles noting 
the color code. 

25. Loosten the covers on all hand lanterns. 

26. Insure that the emergency escape hatch is secured and install the strongback. The 
strongback is topside - must be call:!d for. 

27. Stow and lash down all equipment as necessary. 

28. Vent the emergency fresh water tank and the water heater at high points as necessary. 

29. Secure all electrical circuits except those requested by NOTS to remain on during rais- 
ing. (Lights, open microphones, inclinometer) 

30. Ascertain that the inclinometer is working. 

31. Close all valves on the external gas cylinders. Leave D2 and E2 open. 

32. Close internal gas valves G, H, J, and Jl. Test with topside that air can be provided to 
Sealab via umbilical while raising ai:d that pressure inside Sealab can be measured. 

Note : When valves are aligend as indicated in items 31 and 32, topside must be capable of read- 
ing pressure inside Sealab at all times and must be able to provide air pressure to 
Sealab. In general, all bottom self-supporting systems shall be secured while topside 
control systems shall be operable. 

33. Swim around Sealab to check for loose lines, etc. During this check be sure that all 
protective valve caps are removed. 

34. Secure all hookah/Arawak vaVes and dispose of the hose. 

35. Vacate Sealab, close the main access hatch and bolt down with one dog. 



HANDLING CHARACTERISTICS 105 

36. Pressurize Sealab to 10 psi over bottom pressure with air, or about 100 psi gage. 

Comment: This ends the activities which will be accomplished by the Sealab inhabitants. All 
other activities will be accomplished by surface divers after the Sealab inhabitants 
have been transferred via PTC to the DDC and decompression has started. 

Phase 2 

Sealab 11 has been vacated with main access hatch dogged down with one dog, and pressur- 
ized to 15 psi over bottom, which is about 100 psi gage, depending on tide conditions. Important : 
Bottom is defined as the lower portion of the pressure hull. The reason for this selection of a 
depth reference point is that the main access hatch is very near this point. This main access 
hatch as well as the two other hatches on Sealab must always have positive internal pressure 
to ensure that they are sealed. This is particularly true of the main access hatch which is 
large and does not have an internal strongback to resist negative pressure. 

The pneumofathometer hose will be attached to the top rail of the walking flat, which is 16 
ft above the bottom to the pressure hull of Sealab. Thus, 16 ft must be added to the pneumo- 
gage to get the depth at the bottom of the pressure hull, the depth reference point. 

Pressure inside Sealab will be measured via the sampling line in the umbilical. Similarly, 
air pressure may also be supplied to the Sealab via the umbilical. 

Sealab is on bottom with 6 degree port list and trim by stern of 6 degrees, with spades 
completely dug into the bottom. 

Phase 2 Operations 

1. Move staging vessel over Sealab. This will be about a 55 ft move. 

2. Modify counterweight to handle a 12,000 lb load since it is believed that a minimum of 
2000 lb of water will be left in C-2 after blowing. 

3. Make all dogs tight on main access hatch. 

4. Ensure that Valve B-3 is closed. 

5. Open skirt vent valve A9 to flood skirt. 

6. Pressurize Sealab to 15 psi over bottom if not previously possible since one dog may 
not have been sufficient to hold pressure. 

7. Place Gear in moor (2nd day). 

8. Attach pneumofathometer gage hose to top life rail of walking flat. This point is 16 ft 
above bottom of pressure cylinder. Therefore 16 ft at depth must be added to get depth at 
bottom of pressure cylinder. 

9. Attach lifting wire to the lifting bridle of Sealab and put on small counterweight to take 
slack out of lifting wire. 

10. Close flood valves CI, C2, C3 and vent valve A-8. Leave C4 open so that any air ex- 
pansion in conning tower can be equalized as Sealab is raised. 

11. Check that vent valves A2, A3, A4, A5, A6 and A7 are open. 

12. Check that all valves on topside air salvage system are closed. Open valves Bl and B2. 
This will equalize pressure between the living compartment and tanks 1,2, and 3. Open valves 
A-10 and then A-1 to test air system. Then close A-10 and A-1. 



106 HANDLING CHARACTERISTICS 

13. Inspect 3-1/2-in. nylon at bull nose attached to buoy. If line is good, remove buoy and 
bend additional line and pass to Gear. 

14. Attach 3-1/2-in. nylon to stern bull nose of Sealab and lead to No. 2 Station aboard 
staging vessel. 

15. Disconnect and remove counterweight and dumb waiter system. 

16. Open valve A- 10 and then A-1. 

17. Open valve C2 to blow tank 2. While tank 2 is blowing, maintain pressure in Sealab and 
blowing system via the air salvage hose, and then the umbilical as an alternate means for pres- 
surization to 15 psi over bottom. Caution : Do not exceed 125 psig. 

18. The normal lift off weight of Sealab should be about 12,000 lb. However, due to the 6 
degree list and trim, tank C-2 cannot be blown clean of water until Sealab is reasonably level. 
The water remaining in C-2 after it is blown at the present 6 degree list and trim is estimated 
at 2,000 lb. It may be necessary to take a pull at the stern bull nose with 3-1/2-in. nylon at 
about 5000 lbs. to help level Sealab before it leaves bottom in addition to the 12,000-lb pull on the 
lifting wire. 

19. As C-2 is being blown, take a moderate strain of about 12,000 lb and observe inclinom- 
eter. Assist in leveling Sealab with 3-1/2-in. nylon at stern buUnose staging vessel station 
No. 1. 

20. When C2 starts to bubble when Sealab is level, close valve C-2. Then close A- 10 and 
then A-1. C-2 may not be left open since pressure inside Sealab would drop to at least less 
than bottom pressure at the main access hatch. A-1 and A- 10 are closed to isolate the system 
in the event of failure in the air salvage system while raising. 

21. Take a strain of at least 12,000 lb to lift Sealab off bottom. This may require a con- 
tinuing pull of 30 minutes or more to break out the Sealab spades. The nylon lines at bow and 
stern may be used to assist. Note attitude of Sealab via inclinometer. Note any change in in- 
ternal pressure of Sealab and look for leaks. 

22. After Sealab is off bottom hoist slowly to 60 ft, noting any pressure changes in Sealab. 
Maintain not less than 15 psi in Sealab over bottom at all times in the event of air leaks by 
adding air thru umbilical. 

Note: Tanks and Sealab are isolated from the salvage air system by having valves A-1, A- 10 
and A- 8 closed. Keep moderate strain on nylon lines to keep Sealab from rotating. 

Phase 3 

Sealab at 60 ft to bottom of pressure cylinder and basically perpendicular to stern of 
Berkone pneumofathometer gage reading should be 44 ft (60-16). Pressure inside Sealab, if 
there are no leaks, should be essentially the same as it was on the bottom or about 100 psig. 

At the 60 ft stop do following: 

a. Inspect for leaks 

b. Remove excess lines 

c. Attach 2 6-in. nylon lines from fore and aft bull nose to stations 1 and 2 of Berkone. 
Similarity pass 2 6-in. nylons to station 3 and 4 of the Gear. See sketch. 

d. Rotate Sealab clockwise about 90 degrees so that it is roughly parallel to the stern of 
Berkone. 



HANDLING CHARACTERISTICS 107 

e. Vent interior of Sealab to 15 psi over bottom (bottom of pressure cylinder), thru the air 
salvage hose by opening valves A-1 and A- 10 and venting thru topside manifold. This will re- 
lieve excessive pressure inside Sealab. Pressure inside Sealab should be (.445 x 60) plus 

15 = 42 psi gage. 

f. If necessary blow tank No. 2 by opening valve C-2. 

g. Close valve A- 10 

Raise Sealab slowly to 30 ft, always maintaining 15 psi over bottom in Sealab thru umbil- 
ical air supply. 

Phase 4 

Sealab at 30 ft (to bottom of pressure cylinder) Pneumofathometer reading should be 14 ft 
(30-16). Internal pressure of Sealab should remain as at 60 ft stop, (42 psi gage) assuming no 
leaks. No further changes will be made in Sealab pressure or in tanks 1, 2, 3 pressure until 
Sealab is surfaced. 

Note: At this depth the point of interest will shift from Sealab and ballast tanks 1,2, and 3 to 
the conning tower. Pressure in Sealab will be kept to at least 15 psi over bottom. At 30-ft 
depth the top of conning tower hatch will be 11 ft below the surface. The conning tower top 
hatch has been tested to 15 psi. Therefore 15 psi can be applied to blow out the water and 
should the top hatch break surface in a swell, the hatch should hold this pressure differential. 

At the 30-ft stop accomplish the following: 

a. Check that bolts on top conning tower hatch are tight. 

b. Have Gear take light strain on No. 3 and 4 lines to keep Sealab clear of staging vessel. 

c. Make overall inspection of Sealab. 

d. Check that bolts on main access hatch are tight. 

e. Adjust air in salvage hose to 15 psi. 

f. Ensure valve C-4 is open. 

g. Open valve A- 8 slowly. 

Maintain not more than 15 psi gage on salvage hose and gradually blow water out of conning 
tower. As Sealab gets lighter gradually pay out raising wire and raise counterweight to allow 
Gear to pull Sealab from the staging vessel by gradually increasing pull on lines 3 and 4. 

When conning tower is blown clear keep Sealab about 40 ft from staging vessel. 

Close valve A-8 first and then C-4. Sealab should now float at midpoint of conning tower. 

Phase 5 - Sealab on Surface 

Sealab on surface with conning tower blown. It should have a buoyancy of 6 tons or about 
13,000 lb. It should float at midpoint of conning tower. 

Maintaining 15 psi over bottom (bottom of pressure vessel) ensure that valves A2, A3, A4, 
A5, A6, A7, B-1 and B-2 are open. Open valve A-10. 

Open first valve CI and then C3 to blow water out. Caution : Maintain 15 psi over bottom 
at all times . The compressed air atmosphere must not be reduced at this time by using only 
the compressed air in Sealab, as this may produce negative pressure on the large access hatch. 



108 HANDLING CHARACTERISTICS 

Caution : Great care must be exercised so that the tanks 1 and 3 are blown symmetrically. 
It may be desirable to blow the bow (tank 1) slightly ahead of the stern; the stern may then be 
corrected (lifted) by blowing air into the skirt or by control of valves CI and C3. 

Caution : Valves A-2, A-3, A-6 or A-7 may not be used to control trim as this may pro- 
duce a dangerous pressure differential in the tanks. 

When tanks 1 and 3 are blown clear, Sealab will float at the normal waterline of about 
1 ft-8 ins. Close valves C-1 and C-3. 

Check that valve A- 8 is closed. Vent conning tower by opening valve C-4. 

Gradually vent Sealab via the salvage hose ensuring that large access hatch is holding. 

Warning: Sealab may not be entered at this time until it has been ventilated with air suf- 
ficiently to support life^ 

a. Open conning tower top hatch 

b. Ensure conning tower air can support life. 

c. Bail lower conning tower hatch well. 

d. Open lower conning tower hatch. 

Caution : Do Not enter Sealab. 

Ventilate interior of Sealab with air from the rough umbilical and other means until O2 
content is sufficient to support life and that toxic gases are not present. 

Enter Sealab, with safety line tended by man in open air. 

When atmosphere in Sealab is safe, perform tasks as required. The first should be placing 
strongback on large access hatch and secure. 

Prepare Sealab for tow. Refer to towing bill. 

Gear Take Sealab in tow to Long Beach. Speed not to exceed 4 knots. 

RIG FOR SURFACE TOW OF SEALAB H AFTER RAISING 

1. Install strongback on main access hatch and bolt securely. 

2. Install towing lights. 

3. Check internal pressure port bolts for tightness. 

4. Check that equalizing plugs on each viewing port are open from the outside. 

5. Install external protective covers on the viewing ports. 

6. Make provisions to supply air from the towing ship Gear in event of emergency. 

7. Secure all systems and switch off power. 

8. Vacate Sealab and shut the lower conning tower hatch securely. 

9. Shut upper conning tower hatch and bolt down securely. 
10. Install and test the atmosphere gas loss alarm. 



HANDLING CHARACTERISTICS 109 

11. Assuming that all vent, flood, and equalizing valves are shut, open one vent valve on each 
of the main ballast tanks. 

12. Open the equalizing valves Bl and B2. This will equalize pressure between the ballast 
tanks and the living compartment. 

13. Charge Sealab with air to 20 psi gauge through the gas supply line of the umbilical. This 
will keep all hatches and battle covers tightly secured. 

14. Flake umbilical around conning tower. 

15. Close all valves except A9 and any valves necessary to supply air to Sealab via umbili- 
cal while under tow. 

16. Attach towing rig. 

17. Energize towing lights. Sealab is now ready for tow. 

18. Take Sealab in tow with speed not to exceed 4 knots, following shallow water coastal 
route. Have two men from the Sealab program aboard that know Sealab and its systems well. 

19. If alarm shows air loss, resupply air via the umbilical. In the event Sealab starts to 
sink, head for the nearest shallow water and beach it. 



Chapter 16 
SEALAB II ATMOSPHERE CONTROL 

W. F. Mazzone 
Submarine Medical Center 
New London, Connecticut 

INTRODUCTION 

Sealab II was initially charged with a mixture of compressed air and helium, producing an 
atmosphere which contained 4.5 percent oxygen, 17.4 percent nitrogen, and the balance (78.1 
percent) helium. With relatively small changes, this basic atmosphere was maintained through- 
out the entire operation. 

Pressure within the habitat, as read out on the gage in the atmosphere control van, averaged 
100.7 pounds per square inch absolute (psia), equivalent to a gage depth of 193 ft. Variations 
with the tide were from 191 to 196 ft gage. 

ATMOSPHERE ANALYSIS 

During the entire period in which Sealab II was occupied by personnel, frequent monitoring 
of the habitat atmosphere was carried out in the atmosphere-control van of the support vessel, 
Berkone. A sampling line incorporated in the umbilical to the habitat permitted direct sampling 
of the Sealab atmosphere at any time. The analysis was performed by gas-absorption chroma- 
tography, using a modified Fisher -Hamilton gas partitioner. This method gave good results for 
oxygen, nitrogen, and carbon dioxide, but would not measure helium directly, since helium was 
used as the carrier gas. Helium concentration was estimated by subtracting the total of the 
three measured gases from 100 percent. Commercially prepared standards of oxygen, nitrogen, 
and carbon dioxide in helium (all in approximately the concentrations being measured in the 
Sealab atmosphere) were used to calibrate the partitioner. 

Analysis for trace quantities of hydrocarbons in the habitat atmosphere were carried out 
by Doctor Merle Umstead of the Naval Research Laboratory, using a gas-liquid chromatographic 
method. Samples for these analyses were obtained by opening evacuated steel bottles in Sealab 
II, then reseating them and sending them to the surface. This method prevented hydrocarbon 
contamination of the samples, which would have resulted from passing them through the rubber 
sampling hose. Many chromatographic peaks were found, indicating the presence of minute 
quantities of many different organic compounds. Full identification of these compounds is as 
yet incomplete. 

Some of these steel flasks were returned to Doctor Ray Saunders at the Naval Research 
Laboratory for further analysis. Precise carbon monoxide measurements have been requested 
on these samples. 

Semiquantitative analyses were made for carbon monoxide both topside and in Sealab, using 
portable tube-type detectors (Draeger, MSA, and Kitagawa). These analyses yielded no positive 
results, except in the case of carbon monoxide. On several occasions, carbon monoxide levels 
in the range of 20 to 30 parts per million were indicated by the tubes. These techniques are 
rather inaccurate at low concentrations. One sample was analyzed by the Linde Corporation, 
with results on two determinations of 20 and 20.5 parts per million. It is hoped that other 
accurate carbon monoxide measurements can be made on some of the samples returned to NRL. 



110 



ATMOSPHERE CONTROL HI 

Carbon monoxide was implicated as a possible factor in the headaches which troubled a number 
of the aquanauts. This points up the importance of providing future Sealab operations with a 
sensitive, accurate method of measuring carbon monoxide in the habitat atmosphere, in the 
scuba bottles, and in the compressed air used in charging the personnel-transfer capsule and 
the deck decompression chamber complex. No such apparatus was present for Sealab II. 

Relative-humidity measurements were made in the habitat, using wet -bulb and dry -bulb 
thermometers. Special correction factors had to be introduced because of the increased thermal 
conductivity of the Sealab atmosphere. Relative -humidity values ranged from 60 to 92 percent, 
staying mostly between 65 to 85 percent. 

Temperature of the habitat atmosphere ranged generally from 80° to 90°F. 

ATMOSPHERE CONTROL 

The principal controlling mechanism used was the Krasberg oxygen sensor and controller, 
which automatically regulated oxygen levels in the habitat. The Krasberg controller was set 
for 4.25 percent oxygen (PO 221 mm Hg) during most of the run, with limits of 4.0 percent 
(208 mm Hg) and 4.5 percent (234 mm Hg). It functioned well and in general maintained atmos- 
pheric oxygen within prescribed limits. Near the end of the stay of Team 2, oxygen was reduced 
to approximately 3.5 percent for two days to test the effects of this change on personnel. The 
lowest level actually recorded was 3.28 percent. 

In the first few days of the run, it was found that the water level in the trunk tended to rise 
rather rapidly, and had to be blown down with additional gas every few days. After the stopping 
of some small gas leaks from the habitat, blowdowns were much less frequently required. The 
blowing was accomplished with either compressed air or helium, depending upon the oxygen 
level in the habitat at the time. During these early days it was not necessary to bleed any 
oxygen into the habitat to maintain the desired oxygen tension. This was attributed initially to 
the compressed air used in blowing down. Later in the stay of Team 1, however, it was dis- 
covered that compressed air was leaking into the habitat through the pneumatic air hose to the 
pneumonfathometer. This apparently accounted for the rise in nitrogen during the second week, 
when it reached a peak of 25.2 percent. 

Carbon dioxide was controlled by means of a specially designed manifold which held twelve 
standard canisters (6.2 lb) of lithium hydroxide. This scrubber maintained very low levels of 
carbon dioxide (undetectable to 0.02 percent) for periods of 24 hours or longer. Carbon dioxide 
would then increase rather rapidly, usually reaching 0.25 percent within about 36 hours after 
the canisters were changed. At this level (1.7 percent effective at sea level), the aquanauts 
often were aware of some increase in their rate of breathing and mild discomfort. Canisters 
were usually changed before carbon dioxide reached 0.3 percent, but on one occasion it rose 
to 0.42 percent (2.9 percent effective). After canister changes, carbon dioxide concentration 
fell precipitously, often falling below 0.01 percent in but a few hours. Efficiency of carbon 
dioxide scrubbing was somewhat diminished late in the run, when some of the lithium hydroxide 
canisters were replaced with Hopcalite and some with silical gel for humidity control. The 
principal effects were shortening of canister life by a few hours and raising of minimum carbon 
dioxide levels from below 0.01 percent up to 0.02-0.04 percent. 

Carbon monoxide removal was not included in the planning for Sealab II, as it was not ex- 
pected that carbon monoxide would occur in significant concentrations. When carbon monoxide 
levels of 20 parts per million or more were detected, two lithium hydroxide canisters were re- 
placed with Hopcalite and silica gel for catalytic oxidation of carbon monoxide. This measure 
appeared to lower the carbon monoxide to 10 to 15 parts per million (according to the rough 
measurements available), and no further headaches were reported. 

Hydrocarbons and odors were controlled by the insertion of large filters of activated char- 
coal into the atmosphere recirculating system. Samples of this charcoal bed have been sent to 
NRL for further analysis. 



Chapter 17 
THE DECOMPRESSION COMPLEX 

D. C. Pauli and G. P. Clapper 

Office of Naval Research 

Washington, D.C. 

and 

W. P. Frost 

U.S. Navy Mine Defense Laboratory 

Panama City, Florida 

INTRODUCTION 

The at-sea decompression of ten divers saturated at a depth of approximately 200 ft pre- 
sented new problems for the U.S. Navy. First, the men would have to be lifted from the ocean 
floor in a personnel transfer capsule (PTC), maintaining the ocean-floor pressure, to the 
surface -support vessel; second, they must be transferred to a larger, more comfortable deck 
decompression chamber (DDC); and then they finally must undergo the lengthy decompression — 
approximately 30 hours — at the prescribed 6 ft per hour linear decompression schedule. 

Alternate modes of decompression were possible, but in view of accompanying problems 
and the general need of the Navy to have experience in use of mating PTC/DDC decompression 
complex systems, these alternate solutions were not considered. Alternate solutions available 
were: 

1. Use of the habitat as the decompression complex — This solution would require lifting 
the habitat for each crew change or decompression of crews at depth, with later free ascent, 
which would considerably complicate the design of the habitat. 

2. Use of the PTC as not only a transfer capsule, but also as the main decompression 
chamber — This was done on Sealab I, where a smaller crew (four men) was involved. Reason- 
ably comfortable space for ten men for the duration of the decompression would require a 
much larger PTC and associated difficult at-sea handling problems. Further, the PTC, if thus 
occupied, could not serve as a refuge or for lift of the following team should an emergency 
arise. 

The concept of shuttling aquanauts from surface to the habitat, where they become satu- 
rated, and then back to the surface for decompression placed certain back-up safety require- 
ments on the system. The possibility of contamination of the atmosphere within the habitat 
required that a refuge be available to the aquanauts that had the necessary self-contained life- 
support systems. The possibility of the surface-support vessel losing one or more legs of its 
moor implied that the support-vessel winches might not be readily available in an emergency 
to lift the PTC to the surface; thus, the PTC should be equipped with a self-contained raising 
subsystem. 

PTC -DDC SYSTEM 

PTC Functional Requirements 

The following are the functional and design requirements to which the PTC was designed. 
The PTC was to be: 

112 



DECOMPRESSION COMPLEX 113 

1. Sufficiently large to transport ten aquanauts. 

2. Designed to ASME unfired boiler-code specifications to withstand an internal pressure 
of 200 psig. 

3. Provided with a life-support system which could be operable internally and which could 
maintain the ten personnel for a minimum of 12 hours. 

4. Provided with an internally controlled raising system which would allow personnel un- 
der pressure to raise themselves to the ocean surface. 

5. Equipped with systems for communicating with surface personnel. 

6. Provided with necessary appurtenances for being lifted and handled by the surface- 
support vessel. 

7. Provided with a system for mating the PTC with the DDC. 

DDC Functional Requirements 

The following are the functional and basic design requirements of the DDC: 

1. Sufficiently large to decompress, in relative comfort, ten aquanauts. 

2. Designed to ASME unfired boiler-code specifications to withstand an internal pressure 
of 200 psig. 

3. Provided with a life-support system to be operated externally for decompression. 

4. Provided with a medical lock and an outer lock. 

5. Provided with an overhead flange and hatch for mating with the PTC. 

PERSONNEL TRANSFER CAPSULE 

A simplified cross-section view of the PTC is shown in Fig. 51, and its mated position on 
the DDC is shown in Fig. 52. The PTC being lifted from the water, transferred, and mated to 
the DDC is shown in Figs. 53, 54, 55, 56, and 57. The basic controlling dimensions of the PTC 
were: diameter, 6 ft; height, 11 ft; entrance hatch diameter, 27 in. The cylindrical portion of 
the unit was 8 ft long. Four pipe -type flared legs provided the necessary PTC mounted guides 
for mating. These legs, extending below the mating flange, also provided necessary protection 
to the mating surface during the handling of the PTC without its stand. The stand for the PTC 
provided adequate room (5 ft) below the PTC to gain entrance through the hatch. Ballast to 
provide negative buoyancy for the PTC was contained in two lower ballast trays at the base of 
the stand. The upper tray was permanently affixed to the stand; the lower tray was clamped to 
the upper tray during normal recovery operations by the crane of the surface-support vessel. 
The emergency self-contained raising system for the PTC was, basically, a pneumatically 
controlled, "Green-Giant" sized clock escapement mechanism as shown in Fig. 58. The ratchet 
gear is fixed to the cable spool shaft. One end of the cable is fixed to the upper ballast tray. 
The other end of the cable is fixed to the lower ballast tray. When the lower tray is released 
from the upper tray, the resulting 2000 lb of net buoyancy of the PTC, its stand, and upper bal- 
last tray provides the necessary lifting force. Were it not for the pawls and the pneumatically 
controlled escapement arm, the PTC then would freely ascend to the surface on its cable, and 
the lower tray would serve as an anchor. The positions of the pawls and the escapement arm 
are controlled by the pneumatically controlled piston actuator. Each side of the actuator piston 
can be connected by means of a three-position control valve to either PTC internal atmosphere 
or to the low-pressure side of the He gas regulator. Thus, if both sides are connected to the 
internal atmosphere, the piston will float and the escapement mechanism will run free, the 
cable pay-out speed and hence the ascent rate being only a fimction of the buoyancy, dynamic 



114 



DECOMPRESSION COMPLEX 



Seats 



Fig. 51. Personnel transfer capsule, cross section 




Deck Grating 



Mating Hatch 



drag, and the mass-arm length relationships of the escapement mechanism. An ascent rate of 
about two to four feet per second will result from this free-running condition. The other two 
positions of the controller result in the actuation moving the escapement arm upward or down- 
ward, respectively, and thus permitting the ratchet gear to move one tooth (7 in.). Actuation 
up and down of the control, thus, permits the PTC to be raised slowly and positively to the 
surface. Three ports were incorporated into the structure to permit observations of the occu- 
pants. Internal pressure gages were so placed as to permit their observation from outside as 
well as inside. 




Position of mated PTC 



@ 




x^ 



Fig. 52. Deck decompression chamber, cross section 



DECOMPRESSION COMPLEX 



115 




Fig. 53. Personnel transfer capsule 
being lifted out of the water 




Fig. 54. Personnel transfer capsule being 
transferred from the ocean to the surface- 
support vessel 



116 



DECOMPRESSION COMPLEX 




Fig. 55. Personnel transfer capsule 
sitting on its stand on the deck of the 
surface -support vessel 




Fig. 56. Personnel transfer capsule being 
transferred, with stand removed, to the 
deck decompression chamber 



DECOMPRESSION COMPLEX 



117 




Fig. 57. Personnel transfer capsule just before 
mating to the deck decompression chamber 




gas connections 



Fig. 58. Personnel transfer chamber escapement mechanism 



118 



DECOMPRESSION COMPLEX 



The life -support system consisted of 200 cu ft O2 and He bottles strapped to the exterior 
with pertinent connections, penetrations, and control valves. Regulators, control valves, and 
an Ot flow meter were installed internally for aquanaut control. A standard portable five- 
canister CO2 scrubber was installed with an externally mounted pressure-compensated lead- 
acid storage battery power supply. A solid-state converter thus permitted operation by the 
external battery, to provide 12 hours of effective CO 2 removal. An umbilical provided power 
from the support ship for normal scrubber operation, as well as for internal lighting. Gas- 
sampling and gas-filling hoses were included in the umbilical for normal surface control of the 
PTC atmosphere. 

Communications with the PTC were provided by sonic and wire links. The wire link, con- 
necting with the control-van intercom, was combined in the PTC umbilical. The sonic link 
consisted of an Aquasonic transducer mounted externally and an Aquasonic surface type control 
panel mounted internally. 

DECK DECOMPRESSION CHAMBER 

The DDC is shown in Figs. 59 and 60. It contains berthing for ten men, an entrance lock, 
a medical lock, a CO2 scrubb ;r, a gas-supply manifold, exhaust manifold with constant-flow 
regulators, and a mating hatch for the PTC. It is 23 ft long and 10 ft in diameter. The DDC is 
designated to be operated without any internal electric power to minimize fire hazard under 
high O2 decompression. The CO 2 scrubber is driven by an external motor with a rotating- 
shaft seal through the pressure hull. Lighting is provided through upper light ports. An elec- 
trical appliance outlet is provided; however, a key switch prevents its use except by the medical 
officer. 




Fig. 59. Deck decompression chamber, showing 
mating hatch and "tube turn" clamping ring 



DECOMPRESSION COMPLEX 



119 




Fig. 60. Deck decompression chamber 



PTC-DDC OPERATIONS 

In normal operations, with the PTC on the sea bottom, the saturated divers enter and close 
the hatch in the bottom of the capsule, thereby sealing themselves at bottom pressure. The 
PTC is then hoisted aboard the support vessel and set on deck. The chamber is removed from 
the stand and base (Fig. 55) and placed on the mating hatch of the DDC (Figs. 56 and 57). The 
PTC is sealed to the DDC by means of a "tube turn" clamping ring (Fig. 59). The pressures in 
the PTC and DDC are equalized, and the hatches of the PTC and DDC are then opened. The 
divers then enter the DDC from the PTC, close the DDC hatch, and undergo decompression. 
The PTC is then returned to the ocean floor as the emergency capsule for the next team. 



CHRONOLOGY 

Functional specifications for development of the PTC and DDC were given to bidders on 
Feb. 10, 1965. Dixie Manufacturing Company of Baltimore, Maryland, was selected by a re- 
view board on Mar. 1 to be awarded the design and fabrication contract. After notification of 
contract award on Mar. 10, Dixie immediately initiated detailed design engineering and pro- 
curement of steel and major components for fabrication. 

The steel industries of the United States were threatened with a strike shortly after the 
acceptance of Dixie's proposal. This threat resulted in delay in delivery of the steel for both 
the DDC and PTC. Steel was finally delivered during the last week of May. 

Several other components caused delay to the completion of the chambers. These were: 
oxygen reducing valve for inside the PTC, the medical lock for the DDC, the forged door rings 
for the DDC, and the counterbalance springs for the overhead hatch in the DDC. A number of 
modifications instituted in the basic design from mid-March through delivery by Dixie were 
followed by additional modifications at the Long Beach Naval Shipyard. 



A certification board, headed by Captain L. B. Melson of the Office of Naval Research, 
was appointed by the Chief of Naval Research to review the design and make recommendations 
to insure that the design met safety requirements. This board inspected the PTC and DDC at 
Dixie on July 15. Recommendations of the Board were received on July 23. 



120 DECOMPRESSION COMPLEX 

The PTC was completed and shipped via truck on July 23. The DDC was completed and 
shipped via rail on July 29. 

Upon arrival of the PTC and DDC at Long Beach, a number of modifications were made. 
The emergency release mechanism was tested and, after slight modifications, found satisfac- 
tory. No need was found for its actual use during operations. 

The decompression complex was then installed aboard the support vessel and final check- 
out tests performed. 

During decompression of the three teams, the only unusual operation occurred during the 
decompression of Team 3. At a depth of 23 ft Master Diver Sheets reported pain in one leg. 
Subsequently, Captain Bond entered the chamber via the outer lock, inspected Sheets, and re- 
turned. Hospital Corpsman Manning thereupon entered the DDC, to stay with Sheets during his 
decompression. The other nine aquanauts were moved into the 6-ft outer lock to continue de- 
compression to the surface at 6 ft/hour. Sheets was "sent back down" to 60 ft, given O2 treat- 
ment, and decompressed at a linear rate of 4 ft/hour. 



Chapter 18 
THE SUPPORT VESSEL 



E. P. Carpenter 

Naval Ordnance Test Station 

Pasadena, California 

and 

T. N. Blackwick 
Boston Naval Shipyard 
Boston, Massachusetts 



INTRODUCTION 

The support vessel was originally built for the Polaris pop -up tests conducted by the Naval 
Ordnance Test Station at the San Clemente Island Test Range. The craft consisted of two 110 
34 ft YC barges, spaced 22 ft apart and connected at one end by a covered structure. This ar- 
rangement provided a rigid platform with overall dimensions of 110 x 90 ft with an open well at 
one end with dimensions of 65 x 22 ft (Figs. 61, 62). 





,.^' ". w^fflHB 


■i 




BH 1. CRANE 


wm*^' 




^ 




!■ 2. DIVERS READY ROOM 
■ 3. DOC 




'''""'^QBtolV 


m 




MB 4. S. L. 


^ 










■1 5. LCM-e 


B 










^1 6. LCM-3 


R 


—^^^^^—r^~^— 


^■iiiiiiriiiirniNiiiiiTttiaiMiM^^Mi^^^'^M 






^1 7. MOORING LEGS M 


-^^^■jol 


^^gg&H^^^^H^^^^^Hffl^B 






^1 8. GAS STORAGE PALLETS H 




^^■tt^^^^HH 






Wk 9. LOWERING 


SYSTEM RIGGING OH 




^^^^^^^^M^^^^^^^^l 




^HTr 


^1 10. COMMAND 


CENTER "-; 




^^^^H^^^^H 




^1 II. PTC 
















2h 




^^^^^^H 


^■^IHh 




^K3^HIb 




Hh 


Ih^I 


j^^^^H 




^^^^^^^0^1 




L^^H 


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1 



Fig. 61. Surface support vessel with Sealab II moored nearby 



121 



122 



SUPPORT VESSEL 



s^jf;^-. 



XX= 




Fig. 62. Sealab II surface support vessel 



As configured for the pop -up tests, the support vessel consisted basically of an open well 
with an underwater hinged platform for launcher loading operations, an open missile bay on the 
port barge for missile handling, storage spaces and machinery, equipment, dining and galley 
areas. The principal items of machinery were three ac generators with a total capacity of 460 
kw, two 15,000 lb line pull winches, one high -pressure air compressor, one low-pressure air 
compressor, and a 100-ton Lima crane, restricted to a 50-ton working load as mounted on the 
staging vessel. The machinery was used for Sealab operations without modification. 

MODIFICATIONS 

To adapt the vessel for Sealab support, several modifications were made. The underwater 
hinged platform was removed. A portion of the missile bay was roofed over, and the enclosed 
space used as a divers' ready room with head facilities, showers, and racks for breathing 
equipment and wet-suit drying. The remainder of the missile bay was used for the installation 
of the 10-man Deck Decompression Chamber (DDC) and was fitted with a canvas cover which 
could be removed during Personnel Transfer Capsule - Deck Decompression Chamber mating. 
The space immediately aft of the ready room was fitted out with benches, plumbing, and power 
as required to overhaul and charge the Mk-VI semi-closed breathing equipment. 

On the starboard barge, 01 level, two vans (Fig. 63) with a connecting enclosure were in- 
stalled as the Sealab control center. Included in the vans were communications, atmosphere 
control, and medical equipment. 



Other installations required on the support vessel for operations included the counter - 
weighted lowering system for lowering and raising the Sealab and the Personnel Transfer Cap- 
sule (PTC), the dumbwaiter system for transporting both dry and wet items between the support 
vessel and Sealab (Figs. 64, 65), and the breathing-gas storage and distribution system. 



SUPPORT VESSEL 



123 




Fig. 63. Support vessel medical and communications vans 




Fig. 64. Pressure pot for transferring dry- 
items is lifted into Sealab II entry trunk 



124 



SUPPORT VESSEL 




Fig. 65. Pressure pot for transferring dry items and 
cage for transferring wet itenns are lifted aboard the 
surface support vessel 



LOWERING COUNTERWEIGHT SYSTEM 



In order to safely lower and raise the Sealab between the staging vessel and the bottom, it 
was necessary to make some provision for allowing for the relative motion between it and the 
vessel. It was anticipated that a majdmum relative motion due to wave action, of about 10 ft, 
would be possible during a wave half -period of about 5 sec. Accordingly, a counterweighted 
system, as shown in Fig. 66, was used for lowering and raising both the Sealab and the PTC. 
This system had the effect of maintaining a nearly constant tension on the lowering line during 
the lowering and raising operations. Had this system not been used, the tension in the line 
would fluctuate between zero (free fall of the object through the water) to a value so high as 
would likely part the line or cause other failure of the weakest element. 

Characteristics of the counterweight system as used for the Sealab n Project are shown 
in Fig. 67. 

When operated properly, the system had the very desirable characteristics of smoothly and 
automatically loading and unloading itself when the bottom or surface is reached. The system 
could handle a wide range of loads without changing the size of the counterweight. There are 
theoretically no points of discontinuity, or conditions that would produce shock loads on the 
line, between the load range of zero to infinity. This was not strictly true in actuality, of 
course, since at low loads, fluctuating between and 500 lb at the staging vessel's natural pitch 
period, the counterweight's response would not match the vessel's motion due to its own inertia. 

Operation in this load range (0 to 500 lb) was required on occasions to keep a slight tension 
on the line when the PTC was sitting on the bottom prior to liftoff. This condition was met by 
placing a small auxiliary counterweight directly on the lowering line (allowing it to hang in the 



SUPPORT VESSEL 



125 



SEQUENCE OF LOWERING OPERATION: 








Fig. 66. Sealab II counterweight lowering system 



126 



SUPPORT VESSEL, 




J3 
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SALVAGE TESTS 

DIVER TOOL TESTS 



, POWER LINE 
yWATER LINES 
'■ /'/INSTRUMENTATION LINE 



COMMUNICATION LINE 



Fig. 69. Sealab II operational configuration, artist's conception 



water) and completely removing all effect of the main counterweight by putting excess slack in 
the main lowering wire behind the small counterweight. Both the auxiliary and the main coun- 
terweight systems performed extremely well in all respects. 

DUMBWAITER SYSTEM 

During Sealab n operations, the staging vessel was positioned so that its fantail was almost 
directly above the habitat shark cage (Figs. 68, 69). In this position, a 1/2-inch wire rope was 
attached to the shark cage and brought up to a sheave on the 01 level of the staging vessel, 
passed over a second sheave, and back into the water to a counterweight of approximately 500 
lb. The counterweight served to keep the line taut at all times and to allow for wave and tide 
motions. To transport supplies between the surface and the Sealab, a weighted container was 
loose shackled to the taut wire and lowered and raised with a l/4-in. wire on an air-driven 
winch. For transporting dry items, a pressure container was used which could be vented in 
either direction to equalize its internal pressure before opening. An expanded metal cage was 
provided for transporting wet items although it was usually found more convenient to shackle 
the item direct to the taut wire and lower or raise it without the cage. 

Upon receiving an item at the Sealab it was necessary for one of the subjects to suit-up 
and go out of the shark cage and bring the container inside the cage to a point where it could 
be hoisted up through the access hatch by means of a block and tackle. In the future, this sys- 
tem should be designed in such a manner that it could be operated without the necessity of put- 
ting a man in the water. 



GAS STORAGE AND DISTRIBUTION SYSTEM 

A total of approximately 300,000 cu ft of gas was used for Sealab II operations, the major 
part of this gas consisted of helium, oxygen, and helium-oxygen mix. Approximately half of 
this gas was purchased in bulk and delivered from the vendor's tube trailer directly to Sealab 
receivers consisting of the Sealab interior, the DDC, and, the 24 1300-cu-ft bottles movmted on 
the Sealab. The remainder of the gas consisting mostly of helium-oxygen mixture was deliv- 
ered in "towner" pallets. Each of these pallets consisted of 30 200-cu-ft bottles manifolded 



SUPPORT VESSEL 129 

together. Nine pallets were stored onboard the staging vessel at all times, making a total ca- 
pacity of 54,000 cu ft of gas available. Empty pallets were continually replaced with full ones 
as the gas ivas used. A high-pressure piping system was provided to deliver the gas from the 
pallets to the points of use as needed. These points included the DDC, PTC, Mk VI filling area, 
and the Sealab. 

During the third team's stay on the bottom, a hose was run to the Sealab from the Mk VI 
shop on the Berkone for use in charging the Mk VI bottles in Sealab instead of bringing them up 
for refilling. 

SURFACE OPERATICWS 

With the aquanauts in the habitat, it was necessary that the staging vessel remain in about 
a ten-foot circle. The seaward legs were tensioned to about 10,000 lb. This was for an aver- 
age swell condition, which was three to five feet, and winds of 10 to 15 miles per hour. The 
swells were normally at their worst from about 0200 to 0900. However, at this time there was 
little or no wind. 

The maximum swells experienced were 7 to 8 ft; these were measured with a swell gage- 
Maximum loads of 50,000 lb were experienced inthe weather legs. This was about three times the 
average. These maximum loadings were not a function of the size of the swells at the moment, 
but rather the result of synchronous pitching of the surface -support vessel. Because of this, 
the initial average tension of about 10,000 lb could not be exceeded without producing dangerous 
loads. The elastic limit of the 1-1/4-inch 6 x 19 wire was about 65,000 lb. 

The readout of the tension in the legs was on a Sanborn 150 four-channel recorded. Leg 
No. 2 was not connected; thus, readouts were available under various conditions. These point 
to the necessity of a tension-recording system for open-sea moors. Experience is a poor sub- 
stitute for instrumentation. The safe balancing of forces in the legs is virtually impossible 
without tension instrumentation. For example, in taking in six feet on Leg No. 4, the tension 
increased from 5,000 lb to 30,000 lb. 

The absolute necessity for precision positioning is mandatory in open-sea operations. The 
shore transit stations were satisfactory, and positions of the Berkone could be determined 
within one foot. The mast and the antenna were used as targets. Thus the heading could also 
be ascertained, which was 255° True. The chart for plotting had a scale of one inch for 20 ft. 
The electronic positioning system was satisfactory, but sometimes broke down. The latter was 
Model GDR-T Recorder, made by T. H. Gifft and Associates, of El Segundo, California. If this 
system were more reliable, it would have been satisfactory, although plotting would have been 
more difficult. 

The location of underwater objects around the surface-support ship was likewise extremely 
important. When lowered by crane, this location could be determined by taking bearings on the 
boom. Similarly, anything lowered straight down from the surface -support vessel Berkone or 
a nearby ship, such as the Gear, could be located precisely. However, any of the locations of 
equipment moved by divers was an educated guess, since they knew only their approximate 
position and direction. Under water pingers could not be used to locate objects from the surface. 
Since the aquanauts had no communication with topside during their dives, location by such 
means was not possible. Even reliable one-way comunication would be a tremendous stride. 

One deficiency that was very troublesome was the lack of a remote tripping hook for low- 
ering equipment to the bottom. This is often too dangerous for a diver to do. A jury-rigged 
pelican was used, but it was not satisfactory. Related to this is the necessity of marking low- 
ering wires so that the depth of the hook below the surface can be determined. 

The importance of accurate hydrographic surveys must not be minimized. It is considered 
that the chart used in this operation was one of the best available. Yet, important anomalies 
were discovered. 



120 SUPPORT VESSEL 

The water/air interface is troublesome at best, and particularly so in open-sea conditions. 
The use of a crane to lift the PTC and mate it to the DDC leaves much to be desired. A capture 
system with rigid constraints would seem a far better solution, although such a system would 
be costly. 

One of the most useful movement indicators on the Berkone was the counterweight on the 
dumb waiter leading to the shark cage. The overall range of movement provided an excellent 
indication of sea conditions and synchronous pitching, which produced high loading on the moor- 
ing legs and made handling of equipment with the Berkone crane hazardous. 



Chapter 19 
SITE SELECTION 

D. C. Pauli and G. P. Clapper 

Office of Naval Research 

Washington, D.C. 

and 

T. N. Blockwick 
Boston Naval Shipyard 
Boston, Massachusetts 

INTRODUCTION 

The purpose of the Man-in-the-Sea program is not only to place man at a depth equal to 
any depth encountered on the continental shelf, but also to give him the ability to perform use- 
ful work at these depths regardless of the severity of the environment. 

Sealab I proved that man could survive under 200 ft of water. It remained for Sealab II to 
indicate what useful work could be performed at this depth in an environment typical of the 
continental shelf. 

Therefore, one of the initial concepts of Sealab II was that the operation would be con- 
ducted at a depth of approximately 200 ft with bottom conditions of some severity, i.e., temper- 
ature 45" to 55° F and visibility 50 ft or less. 

With these guidelines in mind, site selection began. 

SELECTION OF GENERAL AREA 

The off-shore site at the Scripps Institution of Oceanography near La Jolla, California 
(Fig. 70) was chosen for several reasons. 

1. The site provided conditions of lower water temperature (48° to 52° F) and lessened 
visibility (0 to 50 ft), as more typical of the conditions under which routine fleet operations 
would be conducted. 

2. The proximity of the excellent research facilities of the Scripps Institution of Oceanog- 
raphy and the Naval activities of the Southern California area enhanced the opportunities of ob- 
taining the maximum results from the experiment. 

3. The proximity of Scripps Submarine Canyon gave an ideal area for excursion diving to 
deeper depths, while precluding the necessity of swimming long horizontal distances. At sev- 
eral points the depth increases from 190 to 300 ft in a horizontal distance of only 100 ft. 

4. The ocean floor from the beach at Scripps Institution of Oceanography out to Scripps 
Submarine Canyon was as well charted as any comparable section of ocean floor in the world 
(Fig. 71). The ecology of the area was also very well known as a result of numerous investi- 
gations by Scripps scientists. This knowledge would give the Physical Oceanographers and 
Marine Biologists in the Sealab teams an excellent basis for further investigations during the 
experiment (Chapters 39,40,41). 

131 



132 



SITE SELECTION 



SEALAB II 
SITE 



10 NAUTICAL 
MILES 



22 NAUTICAL 
MILES 




Fig. 70. Sealab II site vicinity 



SITE SELECTION 



133 




Fig. 71. The three sites considered for Sealab II. Point A - first site picked, 
later deemed unsatisfactory due to great amount of silt. Point B - investigated 
as possible site, but slopes up to 45° made it unsatisfactory. Point C - final 
site selected. The site was covered with three to four inches of silt, and the 
slope was no more than 10°. 



The specific area for emplacement of the Sealab was selected on the basis of detailed bot- 
tom soundings made by the Marine Physical Laboratory of Scripps Institution of Oceanography. 
Figure 71 is a bottom contour chart based on these soundings. The valley area (point A on 
Fig. 71) or its immediate surrounding area was deemed to be satisfactory from oceanographic 
and excursion-diving considerations. Preliminary dives on the site were made in April 1965, 
and the general area was accepted as satisfactory by the steering committee. Dives at point A, 
however, indicated that the valley contained a great amount of deposited silt, and to avoid the 
difficulties of settlement, swimming, etc., the final site would have to be either on the side of a 
hill or further up the valley. 

The surface-support vessel was positioned over point B, Fig. 71, on Aug. 18, and explora- 
tory dives were begun. However, the dives showed that the terrain was more precipitous than 
the charts indicated, with inclinations up to 45 degrees. The visibility was quite poor, only 10 
to 20 ft. The site was considered unacceptable and would, if utilized, require considerable 
wash-out leveling operations and thus jeopardize the project. 



134 



SITE SELECTION 




Fig. 72. The final site as shown on a three-dimensional 
representation of the Sealab II area 



Dives southeast from point A indicated a fairly solid bottom with three to four inches of 
silt and visibility of about 20 ft. The bottom was reasonably flat, with maximum inclinations of 
ten degrees. This site (point C on Jig. 71, and the marking shown on Fig. 72) was considered 
satisfactory, and preparations were then made to lower Sealab 11 in this area. 



chapter 20 
STAGING VESSEL MOORING COMPLEX 

T. N. Blockwick 
Boston Naval Shipyard 
Boston, Massachusetts 

INTRODUCTION 

The site of Sealab II was about 4000 ft offshore at La Jo 11a, California, and almost directly 
west of Scripps Pier. This location made all surface sea operations vulnerable to weather and 
seas from the prevailing western direction. Although bad weather was not expected during Au- 
gust, September, and October, the possibility could not be discounted. 

The two most important open-sea operations of Sealab II were the precision mooring and 
positioning of the surface -support craft and the handling of the Sealab n habitat and the per- 
sonnel transfer capsule (PTC). 

The Sealab habitat is basically a cylindrical unpowered small submarine of about 200 tons 
displacement. The surface -support craft, called the staging vessel or the Berkone, is essen- 
tially two YFN barges joined together. It is 90 ft wide and 110 ft long. 

The mooring aspect of Sealab II was particularly important, for tv/o reasons. First, the 
moor would have to be extremely reliable. Failure of the moor would endanger the lives of the 
subjects in the habitat, although they could be independent of the surface -support craft for a 
limited period of time. Secondly, in order for the surface -support craft to perform its function 
effectively, it was necessary for it to remain within a ten-foot circle, so that equipment could 
be lowered in a precise location (Fig. 73). The positioning of the personnel transfer capsule 
(PTC) near the Sealab II habitat was particularly critical, since aside from its primary function 
of transporting divers under bottom pressure to the deck decompression chamber (DDC), it 
was also an emergency haven for the Sealab divers in the event of an emergency, such as at- 
mosphere contamination, fire, flooding, etc. Further, the ocean bottom in the vicinity was ex- 
tremely uneven and fast changing, with slopes of 45 degrees not uncommon. Equipment could 
not be landed in such terrain, and suitable flat areas had to be pinpointed. The site was near 
the Scripps Canyon, which drops precipitously to a depth of 700 ft. 

To provide for safety in bad weather and precise mobility, a five-leg moor (Fig. 74) was 
designed. Three of the legs were located in the sector of maximum expected weather which 
was from the west. Two of the legs (Nos. 1 and 5) were unique, in that they had to span the 
Scripps Canyon (Fig. 75). 

Each leg was designed to resist a 50-knot wind on the surface -support vessel. This would 
require that each leg be capable of resisting a 50,000-lb pull. To determine the holding power 
of the soil in the area, several anchor tests were made under controlled conditions and a two- 
to-one scope. The holding-power-to-weight ratio was found to be at least seven to one and was 
considered satisfactory. 

The basic leg consisted of the following: 

1. A 13,000-lb Navy Stockless Anchor with a 1-1/4-in. crown wire of length equal to the 
water depth plus 30 ft connected to a 59-in. spherical buoy of 3000-lb buoyancy. 



135 



136 



STAGING VESSEL MOORING COMPLEX 



STAGING VESSEL 




TYPICAL LEG 



Fig. 7 3. Sealab II operational configuration, showing relationships 
of Sealab, staging vessel, PTC, mooring legs, and canyon 



I 30' 30' 
110' \W 



SURFACE 



BOTTOM 




ASR TYPE MOORING BUOY 
1-1/4" WIRE DEPTH + 30' 
^59" SPHERICAL BUOY 



•1-1/4 CROWN WIRE 
DEPTH + 30' 



13,000 LB NAVY 
STOCKLESS ANCHOR 

270'-2"STUD LINK CHAIN 



Fig. 74. A typical mooring leg 



STAGING VESSEL MOORING COMPLEX 137 



LEG #4 
2<)7°T 
930 FT 




N LEG*I 

il** *J 022°T 
1400 FT 



Fig. 75. The staging vessel moor 



2. Three shots of 2-in. stud link chain (270 ft) leading from the anchor to the ground ring, 
where a 9000 -lb clump was attached. 

3. One ASR type mooring buoy connected by 1-1/4-in. wire of length equal to depth plus 
30 ft to the ground ring. No pull would be transmitted through the buoy. The chief purpose of 
the ASR buoy was to permit laying of all but the final connecting wire portion of the moor as 
an entity and to use it for mooring ships and craft during Sealab operations. 

4. Leading from the ground ring with a Miller swivel, 1-1/4-in. 6x19 wire rope was con- 
nected to the surface -support vessel. Although 6x37 wire was specified, 6x19 arrived because 
of an error. This substitute was acceptable, although it was more difficult to handle. 

Two 1-1/4-in. Carpenter Stoppers and Bridles were used to hold the wire at the attachment 
points of the surface-support vessel. After the desired position of the support vessel was 
reached, a short 1-1/2 -in. chain was attached to the tension link. The chain was inserted in 
the system to eliminate chafing of the wire, especially during swells. The tension link was 
connected to a Sanborn 150 four-channel recorder. 

For basic mooring leg, refer to Yards and Docks Drawing No. 1,039,768. 

INSTALLATION OF MOORING LEGS 

All legs, except for the final connecting wires, were laid several weeks (July 12-16, 1965) 
before the surface-support vessel was towed to the site. The legs were lowered in position 
from the bow and then stretched. The USNS Gear (ARS-34) was used to lay the legs. They 
were laid within 25 ft of their planned locations. Two shore transit stations were used to as- 
certain the position of the ship laying the legs. 

The prior laying of these legs facilitated the mooring of the staging vessel when it arrived 
at the site. 

MOORING OF STAGING VESSEL 

In preparation for placing the surface -support vessel in the moor, all the 1-1/4-in. wire, 
except for Leg 5, was placed on the main towing drum of the Gear. The wire for Leg 5 was 



138 STAGING VESSEL MOORING COMPLEX 

placed in stopped bights on the surface -support vessel. The placing of the wire on the towing 
drum would permit easy payout and retrieval of the wire. 

When all was ready for on-site operations, the surface -support vessel was taken in tow to 
the site from the Long Beach Naval Shipyard, which was the staging point for Sealab II. The 
surface-support vessel picked up the 1-1/4-in. wire leading to the ground ring, which was se- 
cured to the mooring spud, and attached it to the 1200 ft of 1-1/4-in. wire. With the aid of two 
YTBs, it drifted back toward Leg 2. At the same time, the Gear attached the wire on the tow- 
ing drum to Leg 2 and steamed toward the surface -support vessel. When within about 100 yd, 
the Gear attached herself to the surface -support vessel with a 6-in. nylon line. The end of the 
1-1/4-in. wire was then passed to the surface -support vessel. She was now in a two-point 
moor. The remaining three legs were run by the Gear in a similar manner. The mooring was 
completed on Aug. 18, 1965. 

It took about eight hours to place the surface -support vessel in the moor. To facilitate 
precise positioning, the wire was marked every 100 ft. It must be fully recognized that to 
maintain adequate tension to keep the wire off the bottom and maintain direction, it is necessary 
to use a ship of the size and horsepower of the Gear. The displacement of the Gear is about 
2000 tons, and it has 3000 horsepower. The laying of Legs 1 and 5, which spanned the Scripps 
Canyon, was particularly critical. Since the 1-1/4-in. wire weighs about 2.5 lb per foot in wa- 
ter, the placing of the wire on the main towing drum for safe handling was almost mandatory. 



Chapter 21 

ASPEaS OF COMMUNICATIONS 
IN SEALAB II PROJECT 

G. P. Clapper, editor* 

Office of Naval Research 

Washington, D. C, 



INTRODUCTION 



Six locations were connected together for routine communications. The communications 
links established were: 

1. Habitat - support vessel 

2. Habitat - shore 

3. Habitat - swimmer 

4. Swimmer - swimmer 

5. Support vessel - shore 

6. Personnel Transfer Capsule - support vessel 



BENTHIC CONTROL 




Fig. 76. Sealab 11 communications block diagram 



*The material for this chapter was contributed by E. P. Carpenter , Naval Ordnance TestStation, 
V. C. Anderson, Marine Physical Laboratory, M. Mackinnon III, San Francisco Bay Naval Ship- 
yard, W. B. Culpepper, and B. L. Cannon, U. S. Navy Mine Defense Laboratory. 



139 



140 ASPECTS OF COMMUNICATIONS 

Commercial telephone lines were used, in addition, for special calls made between Jacques 
Cousteau's submerged Conshelf HI oceanauts and the submerged Sealab II aquanauts, and be- 
tween President Johnson in Texas and CDR Scott Carpenter during decompression aboard the 
support vessel. Special radio and land lines were provided by NASA for providing a communi- 
cation link between CDR Scott Carpenter in Sealab and astronaut Gordon Cooper passing over- 
head in Gemini V. 

HABITAT - SUPPORT VESSEL 

The primary communication link between the habitat and the support vessel was the umbili- 
cal cord. Certain engineering, environmental, and physiological information was also trans- 
mitted through the umbilical cord. The following modes of communication were provided: 

1. Helium speech unscrambler 

2. Electrowriter 

3. Television 

a. Closed circuit monitors 

b. Entertainment 

4. Audio 

In addition to the above, wedge spirometer output and Oj partial pressure were transmitted 
via the communication cable in the umbilical. All equipment was installed at Long Beach Naval 
Shipyard by the Naval Ordnance Test Station according to Mine Defense Laboratory Specifications. 

Exterior Umbilical Cord Connection 

A waterproof receptacle withstanding a minimum hydrostatic pressure of 175 psi without 
leakage was installed on the umbilical conduit provided for the power connections. The con- 
nectors were installed by welding or with bolts and O-ring seals. A waterproof cap with chain 
was provided and installed. The inboard side of the insert of the receptacle was potted to seal 
out moisture after all conductors had been connected. Pressure-proof stuffing tubes were used 
where the cable passed through the bottom cover of the conduit. 

Cable 

The cable from the exterior (umbilical) receptacle to the communication center in Sealab 
was the same as the cable used in the umbilical cord. Table 3 (same as Table 2, repeated in 
this chapter for convenience) lists the conductor and connector usage for each item of com- 
munications gear. The cable used for other interior communication circuits was the Navy or 
commercial type best suited for the application. 

Sealab Communications Center 

A section of the laboratory bench adjacent to the fan cabinet was used for the Sealab com- 
munication center. A patch panel was designed and installed at this location to facilitate con- 
necting the various pieces of equipment at the test site. The panel had multipin receptacles for 
all the TV circuits, and switches for the audio link from Sealab to the support vessel. Table 3 
lists the particular receptacles required to mate with an existing plug on the equipment. A 
panel was also built and furnished to NOTS and was installed in the communications van on the 
support vessel. The panel was identical to the panel in Sealab, except that (a) switches for the 
audio link were not required, and (b) an Amphenol receptacle replaced the two separate recep- 
tacles for the audio link to Sealab and shore. 



ASPECTS OF COMMUNICATIONS 



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142 ASPECTS OF COMMUNICATIONS 

Helium Speech Unsc rambler 

The helium speech unscrambler was provided by the Naval Applied Science Laboratory in 
cooperation with BuShips. Three headsets were provided and were located in the Sealab com- 
munication center, galley, and berthing area. Conductors and connectors are listed in Table 3. 
Unscramblers were located on the support vessel and on shore. The shore unit did not improve 
the helium-speech distortion. The support-vessel unit was used intermittently and was consid- 
ered by some to be marginal. During the visit of Mr. Copel of the Applied Science Laboratory, 
the adjustment of the unit improved the voice materially. Such improvement was not generally 
experienced. 

Electrowriter 

The electrowriter, consisting of a transmitting and receiving unit, was provided by the 
Mine Defense Laboratory and installed by the Naval Ordnance Test Station. Conductors and 
connectors are listed in Table 3. 



Television 

The TV units for monitoring and entertainment were furnished by Scripps Institution of 
Oceanography. Conductors and connectors are listed in Table 3. 

Audio 

The audio link for two-way communications from the support vessel to Sealab was a Bogen 
commercial intercom system. A two- station master was provided for the communication van 
on the support vessel with a remote unit in Sealab. A headset which was compatible with the 
master station was provided for the Sealab communication center. A two-position selector 
switch was provided on the patch panel to permit the selection of the speaker or headset. A 
momentary contact switch was provided as press-to-talk switch to permit the speaker to be 
used as a microphone only when using the headset. 

Wedge Spirometer 

The wedge spirometer was furnished by the Submarine Medical Center and installed by the 
Naval Ordance Test Station. An extension cable with appropriate plugs on each end was in- 
stalled from the communications van to the atmosphere control van. 

O2 Partial Pressure 

The Krasberg unit for determining the O2 partial pressure in Sealab was furnished by 
Westinghouse. Provisions were made to monitor and record the O2 partial pressure remotely. 

Equipment Mounting Strips 

To facilitate the installation of communication and monitoring equipment during the fitting- 
out period, two slotted metal angle strips were installed on the overhead on the surface of the 
cork insulation in the lab, galley, and berthing spaces. The strips were approximately 2 ft 
2 in. on either side of the center line and ran the entire length of each space, except where in- 
terference existed. 

In addition to the systems discussed in the foregoing, which were incorporated in the um- 
bilical cord, two acoustic voice communication systems were provided between the support- 
vessel diving platform and the habitat. The two systems were (a) a Navy submarine voice com- 
munication system, AN/BQC and (b) an Aqua-Sonics voice communication system. Because of 



ASPECTS OF COMMUNICATIONS I43 

the high noise level at the diving platform, the results obtained with these systems were not 
completely satisfactory. 

HABITAT - SHORE 

Benthic laboratory, a multichannel data transmission station was placed on the bottom 
close to Sealab. The following habitat -to -shore links were provided through this station. 

Benthic link 2 - Two-way, push-to-talk microphone loudspeaker. This station was moni- 
tored in benthic control center 24 hours a day. The benthic control watchstander processed 
any call immediately and patched through for two-way communications to the public telephone 
lines or to any control station on the Scripps campus. 

Benthic link 3 - Telephone type handset located at the port watch station. No speaker. Has 
the same capability as benthic link 2. 

Benthic Link 4 - Two-way telephone handset near trunk. This station was not monitored in 
benthic control. Calls had to be organized via links 2 or 3. The other capability is the same, 
but it is intended primarily for a telephone patch. 

Benthic links 5, 6, 7 - Open microphones located in berthing, galley, and laboratory areas 
of Sealab. These microphone outputs were telemetered to shore and could be patched through 
to PIO, the psychological station, or shore control. Most of the time these links were patched 
to the shore control closed-circuit TV monitors. 

Benthic link 8 - Electrowriter receivers but no transmitters were located in benthic shore 
control and at the physiological station. They were not used. 

HABITAT TO SWIMMER 

To enable the swimmer to communicate with the habitat while on a sortie, two means of 
communication were planned. One was a sonic type with a maximum range of 1000 ft, and the 
other was a wire-type intercom with a 300-ft range. 

AQUASONIC UNDERWATER COMMUNICATOR 

Frequency Range: 42 kc 
Modulation: AM 
Battery Life: 80 hr 
Range: 1000 ft 
Depth: 300 ft 

SWIMMER INTERCOM 

Frequency Response: 300 cps - 3 kc 
Battery Life: 40 hr 
Range: 300 ft 
Depth: 300 ft 

The Aquasonic had been used during acoustic tests at the U.S. Navy Mine Defense Laboratory 
with the Mark VI scuba. Four diver units were placed in Sealab II for swimmer use. A surface 
unit was also installed to communicate with the swimmer and/or support vessel. Communica- 
tion tests, intelligibility in particular, were planned using the swimmer units. Due to a crowded 
diving schedule, the first Aquasonic was connected to a Mark VI scuba and tested on day 6. An 
aquanaut tested the rig and attempted to communicate with the habitat. Because of the normal 
back pressure of the Mark VI, the Bioengionics mask lost gas around the edges. This loss 
caused some difficulty in breathing. The receiver section of the swimmer unit worked fine, but 



144 ASPECTS OF COMMUNICATIONS 

according to the listeners in the habitat, all transmission from the swimmer was garbled and 
unintelligible. On day 10 a different swimmer unit was tried with another aquanaut, but again, 
the mask gas loss occurred and the transmission was completely garbled. After this, no further 
attempts were made with the Aquasonic. 

The wire intercoms were tested during Team I's dive. The transmission was completely 
garbled and unintelligible. The same type intercom had been tested at 10 ft at the U.S. Navy 
Mine Defense Laboratory, with very good results. 

SWIMMER TO SWIMMER 

The only type of swimmer to swimmer communication used with any degree of success was 
the standard hand signals which have been used by Navy divers for many years. Development 
of the sonic system discussed in the previous paragraph will add immeasurably to the ability 
of divers to coordinate their underwater work. 

SUPPORT VESSEL TO SHORE 

Several communication links were available through the benthic laboratory. These included: 

Benthic link 1 - Two-way equipment and capability identical to that described in benthic 
link 2. 

Benthic links 9, 10 - Two additional telephone handsets and amplifiers for two-way com- 
munications to benthic control from the support vessel. 

None of the above three links were ever connected or used at the staging vessel end, be- 
cause of an underwater telephone cable which was laid furnishing four telephone lines to the 
staging vessel prior to the installation of the benthic laboratory. Three of these lines were 
commercial telephones connected directly to the Pacific Telephone system, while the fourth 
was a magneto type two-terminal circuit ("battle" phone) connected directly from shore control 
to the support vessel. 

One HF, three UHF, and five VHF channels of communications installed aboard the support 
vessel provided radio communications for the administrative and logistic functions of the oper- 
ations. With these channels, communications were provided for the various support craft, 
Scripps Institution of Oceanography, Mission Bay Aquatic Control Center, and various portable 
and mobile units in the area. Through an unattended relay station on San Clemente Island, the 
range of the radio communications was extended to include Long Beach and Pasadena. 

MISCELLANEOUS COMMUNICATIONS SYSTEMS 

PTC voice communications - The PTC used two systems of communication. The primary 
system was an open microphone in the PTC to an intercom amplifier on the support vessel. 
An Aquasonic system was used as a backup, but proved unsatisfactory. 

Support vessel interior voice communications - A 12-channel interior communication sys- 
tem was installed on the support vessel connecting all primary and normally manned operating 
stations. In addition, an intercom voice communication system from the outside DDC control 
area to the interior of the DDC chamber was used with adequate results. Inasmuch as it was 
vital that the atmosphere van personnel be cognizant of the physical condition of the subjects 
during decompression, a slave station of the DDC intercom was set up in the Atmosphere Con- 
trol Center. 

Benthic and Sealab Television - The TV system for benthic and Sealab used standard 525- 
line interlace scan frequencies. Video transmission was accomplished using five amplitude- 
modulated carriers on frequencies of 51, 60, 69, 78, and 87 MHz. 



ASPECTS OF COMMUNICATIONS 145 

The four cameras furnished Sealab were duplicates of the ones designed for use in Benthic, 
with the exception that the Sealab cameras were not equipped with remotely operated pan/tilt 
mechanism, as were the two cameras used in benthic. 

Three of the four video coaxial connections to benthic, along with telemetered signals for 
focus and sensitivity adjustments, were lost during the initial benthic -to-Sealab hookup as a 
result of the cable-connector damage. 

Both cameras installed inside Sealab functioned normally and transmitted acceptable pic- 
tured ashore via benthic, when either was connected through the one existing good video channel. 
Focus and sensitivity adjustments were made using a jury-rig substitute in Sealab for the lost 
control functions. 

The two underwater cameras outside of Sealab were never lifted out of the mud for testing, 
presumably because there were no additional video channels available for their use, and be- 
cause the limited visibility in the surrounding water discouraged their use. 

Both inside cameras remained operable throughout the 42 days of operation, but they be- 
came less and less usable as a result of many holes burned in the vidicon targets by the fre- 
quent flashing of flash bulbs by photographers in Sealab. It is believed that the vidicons were 
vulnerable because of the low heat-absorption characteristics of the Lucite lens. A piece of 
heat-absorbent glass was taped over the front of the lens of the one camera in use during the 
closing days of the operation, and no additional burns appeared. 

On shore at benthic control, TV carriers were boosted and distributed to various offices 
in the headquarters building and to Sumner auditorium, where they were viewed by officials of 
the project, the press, and the public on standard commercial home entertainment-type TV 
receivers. 

During the operation, additional TV video signals from cameras supplied by Oceanographic 
Engineering Company were brought ashore via separate coaxial cables laid to the Berkone. 
These cameras did not perform satisfactorily in the Helium atmosphere, probably due to helium 
leaking into the case, causing overheating and detuning. The same type of cameras, placed in 
the water outside the habitat looking through the ports into the habitat, performed well, and 
were used as the primary monitoring cameras during the last half of the program. 

Support Vessel Television - Two industrial TV tuners were located in the command van. 
Coaxial cable was run from these to various locations throughout the vessel and to monitors 
which could be switched to either tuner. 

CONCLUSIONS 

Before pressurizing Sealab, the Aquasonic units aboard were opened to ambient pressure 
to ensure that the batteries could be changed at 200 ft. It is felt that pressure on the com- 
ponents had some effect on the intelligibility. Transmissions between support vessel and Sealab 
via Aquasonic were somewhat garbled, but this may have been partly due to the thermocline. 

The Bioengionics mask that was used had straps connecting it to a hood. It was impossible 
to get a tight seal sufficient to prevent gas loss around the edges. The back pressure of the 
Mark VI scuba makes a tight seal imperative. 

The wire-type intercom used a bone-conduction microphone. It was felt that pressure on 
this unit deformed the sides such that the frequency response was severely limited. To verify 
this, a test recording was made in a chamber at 200 ft using the bone phone. The recording 
showed that the increased pressure did limit the frequency response, but not enough to account 
for the distortion noted in Sealab n. 

The present Navy helium speech unscrambler did not provide continuously reliable and 
improved intelligibility, due to either equipment malfunction or maladjustment. 



146 ASPECTS OF COMMUNICATIONS 



RECOMMENDATIONS 



Communications from swimmer to habitat are necessary on some sorties. This need was 
amply demonstrated on Sealab 11. The sonic type has an obvious advantage over the wire type, 
particularly on long-range sorties. Since the Aquasonic is the only long-range communicator 
readily available at this time, testing is needed to determine what causes the garbled trans- 
mission from the swimmer at the 200- ft depth. A better strap design is needed to ensure that 
the Bioengionics mask seals gas tight to the swimmer's face. A redesigned mask might be 
necessary to alleviate this problem. 

In the future, a sonic communicator compatible with helium speech should be developed. 
This commimicator should be much smaller than the Aquasonic and more reliable. 

The swimmer intercom should be investigated to determine the source of distortion. A 
smaller unit with two-way capabilities is desirable and well within the present state of the art. 
A different type of microphone might be necessary 

Improvement in helium speech unscrambling techniques is needed. 



chapter 22 
UTILITIES 

V. C. Anderson 

Marine Physical Laboratory 

San Diego, California 

WATER SUPPLY 

The Sealab water supply was taken from the water main near the pier on the Scripps Insti- 
tution of Oceanography campus. 

Water was piped at main pressure to the outer end of the pier via 1000 feet of 1-1/2-in. 
polyethylene pipe. At the pier end, two 3/4-horsepower helical rotor pumps were provided and 
mainfold connected into the two 3/4-in. schedule- 80-vinyl pipes used for transmission of water 
to Sealab. Each pump was capable of providing an output pressure 70 psi over the source pres- 
sure at 5 gpm flow. After a few days of operations it was determined that main pressure, 
which averaged 75 psi, was sufficient for supplying Sealab. At this time the pumps were by- 
passed and secured. 

The two water lines were laid with and attached to the Sealab power cable (see Power 
Supply for laying procedures). The lines were terminated at the transformer dome in a pair 
of Hansen B6K31 self-sealing couplers. There couplers were secured to the transformer dome 
near its base for easy access by the divers. Check-valve assemblies were coupled at the time 
of installation to permit the line to be flushed with fresh water. Divers removed the check- 
valve assemblies and coupled flexible water hoses for the connection to the Sealab fresh-water 
system. 

POWER SUPPLY 

The power supply for Sealab was taken from a main power distribution pad on the Scripps 
Institution of Oceanography campus. A length of armored four-conductor submarine cable, 
identical to that used on the ocean floor to the Sealab site, was laid along the pier. The pier 
end of the cable was terminated in a high-voltage disconnect switch, while the campus end was 
wired to disconnect when the demand exceeded 100 kva. Transmission voltage was 4160 volts 
3 phase. 

The underwater submarine cable lay was terminated at a point near the Sealab site in an 
underwater transformer housing containing three 37-l/2-kva transformers providing a 3-phase 
440-volt output. The shore end of the cable was connected to the high-voltage disconnect 
switch on the pier. 

INSTALLATION 

The initial installation was made on Aug. 20 using an oil-filled concrete dome 6 ft in diam- 
eter and 6 ft high as a housing for the undersea transformers. The laying procedure consisted 
of transferring the dome with cables and water lines attached to the staging vessel, using the 
staging-vessel crane. The power cable - water pipe bundle was then taken aboard the staging 
vessel and stopped off with a length of nylon line. The cable layer (NEL's YFU-45) then pro- 
ceeded to lay the cable in a direct line to the pier. As the cable payed out from the cable well, 
the water lines fed from their individual ten-foot-diameter spools, and were banded to the 

147 



148 UTILITIES 

power cable just prior to passing over the forward bow sheave. The cable layer tied off to a 
buoy upon reaching the pier and passed the cable and water lines across to a crew on the pier 
end. 

While the power cable was being laid, the staging-vessel crew attempted to place the con- 
crete transformer housing on the bottom. The attempt was unsuccessful; the transformer 
dome was severely damaged by shearing off of the support legs and undercarriage and carry- 
ing off of the cable gland fitting. The rigging crew and divers on board the staging vessel 
were able to salvage the concrete dome and managed to replace it on board the YFU-45 for 
return to NEL. 

A new steel transformer dome was fabricated over the weekend from a surplus air-pressure 
tank previously removed from FLIP. On Aug. 31 the new dome was transported to the Sealab 
site on board the Oconostota, where it was transferred to the staging vessel. The shore cable 
splice was made, and the dome emplanted on the bottom. The shore power and water supply 
were available continuously during the 45 days of the Sealab operation. 



Chapter 23 
OPERATIONAL AND EMERGENCY BILLS 

SEALAB n STEERING COMMITTEE 



INTRODUCTION 

Any operation of the type of Sealab II must be prepared for an emergency. While it is next 
to impossible to provide detailed procedures to cover every emergency that might develop, it 
is possible to provide a set of general instructions which can be applied to nearly all situations. 

The following operational and emergency bills are included in this section: 

OPERATIONAL BILLS 

1. Staging vessel swimmer safety 

2. Sealab swimmer safety 

3. MK-VI maintenance 

4. Personnel Transfer Capsule maintenance 

5. Personnel Transfer Capsule operation 

6. Fresh water and fuel oil 

7. Staging vessel general safety precautions 

8. Duties of Staging Vessel Personnel 

EMERGENCY BILLS (SEALAB)* 

1. General casualty instructions 

2. Accident or illness 

3. Loss of pressure or flooding 

4. Fire 

5. Outside loss or accident 

6. Atmosphere contamination 

7. Electrical power loss 

EMERGENCY BILLS (SUPPORT VESSEL) 

1. Foul weather 

2. Moor slipping 

SWIMMER SAFETY BILL, STAGING VESSEL 
General 

In order to insure the most possible safety for support swimmers and divers, certain cov- 
erage from topside personnel must be readily available. Constant vigilance must be kept for 
any emergency confronting support divers. 

*SEALAB raising and lowering procedures are included in Chapter 15. 

149 



150 OPERATIONAL AND EMERGENCY BILLS 

Diving Operations 

Unless an actual emergency exists, support diving will in all cases be governed by existing 
regulations. All current publications as to weather and state of sea conditions must be adhered 
to. The diving officer on board the staging vessel will in all cases have the final say as to 
whether or not diving operations will be allowed. 

Safety Swimmers 

Two men will be assigned to act as safety swimmers during diving operations. The duties 
of these men will include keeping a vigil for any emergency. They will have at their disposal 
a complete set of diving gear and a safety boat. Both the diving gear and the boat will have 
been checked out prior to diving operations and be maintained in the standby conditions. 

Equipment 

Two Mk VI rigs - charged with 68% He/32% O2 

Two aqualungs fully charged 

Two sets of fins 

Two face masks 

Two life jackets 

Two weight belts 

Two diving knives 

Two depth gauges 

Two compasses 

Two diving watches 

Two day and night flares 

Wet suits - complete 

Buddy line 

Safety boat - motor, oars, gas, resuscitator, first aid kit 

Complete set of decompression tables 

In Case of Emergency 

All further diving operations will cease. The standby swimmers will immediately render 
assistance as needed. Medical aid will be summoned and the recompression chamber readied 
for use. A Minute Man Resuscitator will be available at all times. 

General Surface Dive Procedures for Operation Sealab II 

Normal diving needs during Operation Sealab will require four divers per day. An emer- 
gency standby team comprised of two divers will be assigned for each 24-hour period, com- 
mencing at 0700. Rotation of divers will be such as to allow one day out of three without deep 
diving exposure whenever possible. 

Surface dives to be made on the project will involve diving to depths beyond maximum 
working limits outlined in the Diving Manual; therefore, strict adherence to the following 
safety procedures must be observed: 

1. All bottles used will be gaged and pressures logged on the dive sheet immediately prior 
to the dive. 

2. The following equipment must be worn on all surface dives made: 

Life jacket 
Knife 
Depth gauge 



OPERATIONAL AND EMERGENCY BILLS 151 

Diving watch 

Weight belt (if wet suit is used). Weight belts must be secured in such a manner as to 

be shed easily. 

3. The buddy system will be used on all dives, with the divers remaining close enough to- 
gether to allow return to the diving bell using the buddy breathing system in the event of equip- 
ment failure. 

4. All exposure and decompression times will be maintained by stop watch and recorded 
by the timekeeper in the diving log book. 

5. Divers will be briefed prior to dives on maximum exposure times. Whenever possible 
divers shall leave the bottom two minutes prior to maximum time set for the dive. This rule 
may be exceeded in emergencies. 

6. A 60 ft per minute rate of ascent will be maintained on all dives, with all divers briefed 
on action to be taken in the event of variation from this ascent rate. 

7. Pneumofathometer readings will be used to record diving bell decompression depths. 
Where maximum depth of dive is concerned, and divers do not exit from the Submarine Rescue 
Bell, 5 ft shall be added to pneumofathometer readings to determine depth of dive. 

8. When oxygen is used as a breathing media during decompression, divers shall keep 
their physical activity to a minimum. 

9. It shall be the responsibility of the master diver or senior diver present to see that 
safe diving practices are observed. No divers shall enter the water without permission from 
the senior diver present. 

SWIMMER SAFETY BILL, SEALAB 
Predive Safety 

1. All dives will be planned and discussed with all members of the diving team before 
suiting up. 

2. All dives will be under supervision of an assigned diving supervisor. 

3. Pertinent data including estimated time, location, divers' names, etc., will be logged 
with watch stander. 

4. After suiting up, divers will check diving partner's equipment. 

Diving Safety 

1. Log time of entry into water at the trunk with watch keeper. 

2. Recheck partner's equipment upon submergence. 

3. Abort on any life-support-equipment failure. 

4. All diving will be with an assigned partner. 

5. Because of possibility of zero visibility, no breath-holding dives will be allowed outside 
of shark cage. 

1 

6. Length of dive will be limited to 2/3 of gas-supply duration except in emergency. 



152 OPERATIONAL AND EMERGENCY BILLS 

7. Swimmers will not venture outside established perimeter except in cases of emergency, 
and then with permission from top side. 

8. Communications will be maintained. 

9. An accurate depth gauge will be worn, and no ascents above 33 ft from the Sealab en- 
trance water level will be permitted. Routine descents greater than 33 ft are also prohibited. 

10. Swim groups will carry a pinger receiver to home on the habitat. In zero visibility a 
life line will be carried from the habitat. 

11. All divers will be negative when breathing bags are extended. 

12. SPU operations will be under supervision of Officer in Charge. 

13. Buddy-line communicators or buddy lines will be worn by swim pairs unless permis- 
sion granted otherwise by Officer in Charge. 

14. Bounce dives of greater than 33 ft will be conducted only upon control and discretion of 
the surface command center. 

MK-VI MAINTENANCE BILL 

Each subject in Sealab will be assigned a Mk VI breathing apparatus for excursions outside 
the dwelling. Daily maintenance of the Mk VI will be the responsibility of each individual. 
After each use perform the following maintenance procedures on the breathing apparatus. 

1. Thoroughly rinse the Mk VI with clean, fresh water until all foreign matter is removed. 

2. Inspect inlet filters of regulator, assembly, regulator aneroid chamber, diaphragm 
(once each week), control block assembly, safety rupture disk, exhaust valve assembly, and 
"buddy -breathing" assembly for foreign matter and contamination. 

3. Inspect all rubber components for deterioration, cuts and nicks, and replace parts as 
necessary. 

4. Check for smooth operation and return of bypass valve by pulling bypass lever. 

5. Inspect all cloth material components for breaks and excessive wear. 

6. Separate cylinders and manifold valve assembly from breathing bag and vest assembly. 
Send cylinders and manifold valve assembly topside for recharging. 

7. Dump CO2 absorbent from canister and wipe clean. If canister has been flooded, wash 
thoroughly with fresh water and dry. 

8. Remove exhaust valve from bag assembly. Hang bag assembly and mouth piece "T" 
tube assembly and let dry. 

Preparation of Mk VI for excursion: 

1. Check gas pressure and02 percentage in cylinders, making sure they have been properly 
refilled. 

2. Secure yoke assembly, regulator assembly, control block assembly and properly filled 
canister assembly to the apparatus. 

3. Check regulator assembly and control block assembly for proper pressure setting and 
flow requirements. 



OPERATIONAL AND EMERGENCY BILLS 153 

4. Completely assemble apparatus for diving. 

5. Check all connections as hanson fittings, hose fittings, mouthpiece "T" tube assembly, 
exhaust valve and "buddy-breathing" apparatus. 

6. Check the breathing apparatus for leakage by submerging in water. 

Refer to NAVSfflPS 393-0653 Service Manual for "Mark VI Underwater Breathing Appara- 
tus" for Complete Maintenance Instructions. 

PERSONNEL TRANSFER CAPSULE MAINTENANCE BILL 

The Personnel Transfer Capsule is the means of transport for Sealab subjects between 
Sealab and the Deck Decompression Chamber. It is the subject's transfer vehicle, which takes 
him down at the start of his tour and returns him at the end. Further, during the subject's 
stay in Sealab, the personnel transfer chamber will remain in position near Sealab. It is im- 
perative that it be maintained in constant readiness. Daily checks should therefore be per- 
formed by the subjects. 

The following checks are to be made daily: 

1. Water level 

2. Gas sample 

3. Gas bottle pressure 

4. Scrubber operation. 

Water level in the chamber will rise and fall with changes in tide. Water-level checks 
should be made each day half way between high and low tide. Water level should not be above 
the grating at half tide. Any helium added to adjust water level should be logged. 

Gas sample will be taken daily through gas- sample hose to the gas control van via the 
Sealab gas-control panel. 

Gas bottle pressures for He and Oj should be recorded in the log daily. 

Scrubber shall be turned on momentarily each day to check operation. 

PERSONNEL TRANSFER CAPSULE OPERATIONAL BILL 

Gas Manifold 

The gas supply system for the Personnel Transfer Capsule (PTC) is simple, and very 
flexible. Although designed for operation by the occupants of the capsule, atmosphere control 
can easily be taken over by topside personnel, once the PTC is on deck, and requirements for 
external control exist. This is considered to be a remote possibility, occasioned only by ex- 
tensive delays in the mating procedure or by the necessity of using the PTC for decompression 
purposes. In normal use, the occupants of the PTC will exercise control of the atmosphere, 
adhering to the following protocol. 

Normal Use of PTC 

Before entering the PTC, either topside or on the bottom, two aquanauts will check the ex- 
ternal Ot and He manifold, and open bottle valves to assure that one bottle of each gas is on 
the line to the internal piping system. In the event of anticipated rise to the surface, without 
surface support, all bottles must be opened to the manifold. 



154 OPERATIONAL AND EMERGENCY BILES 

Next, these two aquanauts will enter the PTC (hatch open at all times), and check together 
both the routine mode of gas delivery, via the regulator (outboard) controlled pipeline, and 
next the emergency (inboard) direct-flow system, assuring that all valves operate satisfactorily 
without stick or leak. During this procedure, caution must be exercised to flow only a small 
amount of the gas in each manifold, in order to preserve normal gas balance in the PTC. Once 
satisfactory flow has been demonstrated in both channels on each gas system, and the Oj Flow- 
Rator Tested to 20 cfm for a period not to exceed ten seconds , all internal valves will be 
secured. The PTC is now ready for occupation. 

After all occupants are on board, check O2 level before securing entrance hatch. Prior to 
descent from surface, this should not exceed 25 percent if leaving from the deck, at sea-level 
pressure. If departing from Sealab n depth, O2 level may not exceed 10 percent . In any case, 
overoxygenation can be corrected by inflow of helium, at a slow rate, and with the entrance 
hatch open . Once these requirements are met, the entrance hatch will be shut, and the transfer 
in either vertical direction can be accomplished. 

During transit in either ascent or descent, both O2 and CO2 levels will be checked every 
three minutes . Oxygen levels will not be allowed to exceed 1.5 atmospheres (Strasberg), and 
CO 2 levels must not exceed 0.5 percent (Dwyer). Should these values be exceeded, notify top- 
side, and appropriate orders or measures will be taken. In event of a stay in excess of 3 to 5 
minutes in the PTC, CO2 scrubber operations and O2 bleeding will become mandatory. Since 
CO2 buildup will be a controlling factor, the scrubber should be in operation prior to entrance- 
hatch closure. Oxygen should be bled in, after five minutes, at a rate to maintain a constant 
partial pressure of O2 of not less than 160 mm Hg = 0.2 atmosphere, and not more than 1.0 
atmosphere. In the event of Krasberg unit failure, a safe rule of thumb will be the admission 
of 10 cu ft of O2 every 30 minutes. In event of power failure, the foot-operated CO2 scrubber 
should be operated continuously. Should this latter equipment fail, spread the absorbent in the 
lower flats of the PTC, and expend as little energy as possible. 

Abnormal Use of PTC 

It is conceivable that through loss of mating capability, or necessity of use as a deck de- 
compression facility, the PTC might require external control and monitoring of internal en- 
vironment. Provisions have been made for this unlikely situation. Three access penetrations 
are provided in the design of the PTC to permit complete atmospheric control by topside per- 
sonnel. One of these penetrations will be available for gas sampling, while the remaining 
apertures will be available for decompression exhaust and oxygen replenishment. An external 
CO2 scrubber will be available for use. Thus, even without active participation of the aquanauts, 
decompression can be accomplished within the PTC mounted topside, and without use of the 
Deck Decompression Chamber (DDC). The necessary steps to establish this capability are as 
follows. 

1. In event of delay in the mating of PTC to DDC in excess of ten minutes after return to 
the staging vessel, caps will be removed from inlet and exhaust penetration lines to the PTC, 
and appropriate topside connections made. The inlet line will provide only compressed air . 
The outlet line will exhaust for decompression. No attempt will be made to provide an He/Oj 
mix. Decompression calculations will simply be changed to allow for the different gas mix. 

2. Varying percentages of oxygen will be supplied to the PTC, as dictated by the physical 
condition of the occupants, and the decompression profile. These determinations will be the 
sole responsibility of the Principal Investigator. 

3. Hookup of the CO 2 scrubber system (external) will be dictated by operational circum- 
stances. Should a delay of more than one hour be anticipated, action will be instituted to 
assure incorporation of this life support item. 

4. Communication with, the occupants of the PTC will be maintained throughout, and 
recorded. 



OPERATIONAL AND EMERGENCY BILLS 155 

FRESH WATER AND FUEL OIL BILL 

Fresh water and diesel fuel service connections are located portside aft on the surface- 
support vessel, the diesel-oil connection being directly above the fresh-water connection. Both 
lines are made of 2-in. galvanized pipe. The diesel-oil connection is reduced to 1-1/4 in., and 
the fresh-water connection is reduced to 1-1/2 in. 

When taking aboard fresh water, the tank cover located in the machinery room will be 
opened to lower the chance of flooding the machinery spaces. Located on the after starboard 
side is a 2-in. gate valve used for filling the small tank. When the small tank is within one 
foot of the top, open the second 2-in. gate valve located against the after starboard bulkhead. 
This is the filling line for the large tank. Close the 2-in. valve for the small tank and close 
the cover. It is unnecessary to open the large tank cover, as this tank vents overboard. Secure 
taking on water when the large tank overflows. 

When taking on diesel oil, open the 2-in. gate valve located on the stern, starboard side. 
Soundings will be taken frequently, and when the tank is 95 percent full, secure taking on fuel. 

The duty machinist will take fresh-water and diesel-oil soundings each morning and keep 
a log of the amount of water and oil that is on hand. He will turn into the range supervisor a 
correct finding as to the total gallons of fuel and water remaining on board. 

STAGING VESSEL GENERAL SAFETY PRECAUTIONS 
General Safety Precautions 

1. All barrels of the U.S. Standard (55 gallon) size will be stowed in racks provided on the 
stern of the staging vessel. Spare barrels will be lashed securely to the life lines. Small gas 
cans used in work boats will be placed in the rack provided for them on the stern, starboard 
side. The five-gallon safety fuel cans will be stowed on the stern, portside. 

2. All oxygen, acetylene, and oxygen-helium cylinders will be readily available for emer- 
gency use in racks provided for them on the 01 deck. 

3. All civilian contractor personnel will be required to wear safety hats, shoes, and 
glasses. Safety glasses are to be worn when grinding, chipping, and wire brushing, or when in 
an area where any of these activities are going on. 

4. When civilian personnel are riding aboard a military- controlled boat or vessel, the 
boat coxswain, under the senior line officer aboard, is in complete charge. Civilian personnel 
will at no time interfere with or dispute the orders of the coxswain. 

5. At no time when the ten-man Deck Decompression Chamber is in use will there be any 
welding, burning, grinding, or smoking in the area. 

Starting, Operating, and Maintenance Procedures for Staging 
Vessel Major Equipment 

Ingersoll-Rand L P Air Compressor 

1. Check crankcase oil level with bayonet gage before starting. 

2. Open the unloaders to lessen the load pressure and drain off accumulated condensation. 

3. Turn automatic switch to "on" position, starting compressor. When the compressor 
has attained normal speed, close unloaders. When air pressure has built up to normal pres- 
sure, the compressor will automatically stop and start as air is needed. 



156 OPERATIONAL AND EMERGENCY BILLS 

4. When the compressor has been operated for 500 hours, change the oil and strainers. 
Use straight naphthnic base oil. 

5. The operator will maintain a continuous watch when the compressor is in operation. 
He will also keep the compressor and surrounding area clean at all times. 

Ingersoll-Rand H P Air Compressor 

1. Open outside natural air- supply vent and cut in electric supply air blowers. 

2. Check crankcase for correct oil level. 

3. Open unloaders to lessen load pressure and to drain off accumulated condensation. 

4. Push down the green "start" button and hold until the oil pressure builds up to at least 
35 1b. 

5. Open main valve to accumulator and close unloaders. 

6. When the compressor has been operated for 100 hours, change oil and clean or replace 
filters as required. If operating in a dirty or dusty area, change oil and filters more often as 
considered necessary. 

7. When the compressor is operating, the two exhaust blowers at the after end of the com- 
pressor must be running to pull cooling air across the receivers. If the blowers are not run- 
ning, secure the compressor until the blowers can be started. 

8. The operator will maintain a continuous watch when the compressor is in operation. 
He will also keep the compressor and surrounding area clean at all times. 

60 -kw Generator 

1. Cut in supply and exhaust blower 

2. Check starting batteries for proper charge. 

3. Cut in diesel fuel. 

4. Check oil level in crankcase. 

5. Check cooling water. 

6. Turn the starting switch to the right and hold until the engine starts. 

7. Adjust engine speed to maintain 40 lb of oil pressure. 

8. Cut in control panel and adjust as required. 

9. When the generator has been operated for 30 hours, change the oil (9250) and replace 
the filter. 

10. The operator will maintain a continuous watch when the generator is in operation. Oil 
leaks and drippings will be cleaned up and waste disposed of in a flashproof container. 

200-kw Generators 

1. Cut in supply and exhaust blowers. 

2. Check starting batteries for proper charge. 

3. Cut in diesel fuel. 



OPERATIONAL AND EMERGENCY BILLS 157 

4. Check oil level in the crankcase. 

5. Check cooling water in the sight glass. 

6. Turn on the starting switch. 

7. Pull the starting throttle to the stop until the engine starts, then retard the throttle to 
the center notch. 

8. Adjust the govenor to give the required generator speed and cut in the control panel. 

9. When the generator has been operated for 30 hours, change the oil (9250) and replace 
the filter. 

10. The operator will maintain a continuous watch when the generator is in operation. Oil 
leaks and drippings will be cleaned up and waste disposed of in a flashproof container. 

DUTIES OF STAGING VESSEL PERSONNEL 

Electricians 

Primary Duties — The primary duties of the electricians are to maintain electrical power 
at all times, to make electrical repairs on switchboards, controllers, and motor-generator 
sets, to install light bulbs and fuses, and to repair or replace faulty wiring and cable. 

Collateral Duties — The electrician will turn on outside standing lights and anchor lights 
one half hour before sunset and secure them one half hour after sunrise. During slack time 
he will chip, wire brush, paint, and assist in keeping the vessel clean. 

Shipfitters 

Primary Duties — The primary duties of the shipfitters are to repair all piping, inspect and 
repair washbasins and sanitary equipment, inspect voids and compartments for damage and 
flooding, weigh fire extinguishers, and maintain firefighting and safety equipment in top repair 
condition. 

Collateral Duties — The collateral duties of the shipfitters will be to assist the experimental 
group as requested, to chip, wire brush, and paint where required, and to assist, in general, 
in keeping the vessel clean and in safe operating condition. 

Mechanics 

Primary Duties — The primary duties of the mechanics will consist of repair and mainte- 
nance of machinery and equipment. This will include the repair of outboard motors, diesel 
engines, air compressors, gasoline starting engines, salt- and fresh-water pumps and the 
taking aboard of fresh water and fuel. 

Collateral Duties — The collateral duties of the mechanics will be to assist the experimental 
group as requested, to chip, wire brush, and paint where required, and to assist, in general, 
in keeping the vessel clean and in safe operating condition. 

Machinists 

Primary Duties — The primary duties of the machinists will consist of servicing and oper- 
ating the 200-kw and 60-kw generators, HP and LP air compressors, port and starboard fire 
and bilge pumps, fresh-water pumps, salt-water cooling pumps, and the diesel-oil transfer 
pump. 



158 OPERATIONAL AND EMERGENCY BILLS 

Collateral Duties — The collateral duties of the machinists will be to assist the machanics 
in any repair work. The machinists will also assist the experimental group as requested, and 
will chip, wire brush, and paint where required, and will assist, in general, in keeping the 
vessel clean and in safe operating condition. 

Riggers 

Primary Duties — The primary duties of the riggers are to give standard signals to the 
crane operator, make hookups of all loads that are hooked to a crane or hoist, be familiar with 
the safe work-load tables, be responsible for the safety of all hitches, and be responsible for 
the safe moving of any load. The riggers will also splice wire, nylon, and manila ropes as 
necessary. 

Collateral Duties — The collateral duties of the riggers will be to assist the experimental 
group as required, to chip, wire brush, and paint where required, and to assist, in general, in 
keeping the vessel clean and in a safe operating condition. 

Crane Operators 

Primary Duties — The primary duties of the crane operators are to familiarize themselves 
with the crane mechanism and its proper care, and with all operating safety rules. At the be- 
ginning of each shift the operators shall examine their crane for any defective parts or any 
other condition which would make the crane unsafe. Upon finding such a condition, the operator 
will immediately notify his supervisor. When operating the crane, the operator will accept 
only standard crane signals given by a qualified rigger. 

Collateral Duties — The collateral duties of a crane operator will be to assist the experi- 
mental group as requested, to chip, wire brush, and paint where required, and to assist, in 
general, in keeping the vessel clean and in a safe operating condition. 

General Safety Rules for Rigging and Crane Operation 
Safety Rules for Riggers 

1. Safety shall always be given first consideration in material-handling operations. The 
rigger shall constantly bear in mind that the safety of others, the equipment, and himself de- 
pends upon the safe movement of materials. 

2. Only a designated rigger shall give signals to a crane operator. The signals shall be 
standard crane signals. 

3. The rigger shall be responsible for the safety of all hitches and for the save moving of 
any load that is hooked to a crane or hoist. 

4. All rigging equipment shall be checked for defects before being used. When in doubt 
about the safety of any equipment, the rigger will consult his supervisor. 

5. Hitching equipment shall be properly applied so that the load can be lifted in a secure 
and stable position without danger of dropping, shifting, or turning. 

6. A rigger shall not permit any load to be moved if its weight exceeds the posted capacity 
of the crane or the permissible safe load for the slings being used. 

7. Wire rope and fiber slings shall be protected by the use of softeners at the sharp edges 
of a load. 

8. No one shall work under a suspended load unless the load has been adequately supported 
from the deck. All conditions of this type must be approved by the supervisor. 



OPERATIONAL AND EMERGENCY BILLS 159 

9. The rigger shall not permit anyone to pass under any suspended load that is being 

moved. 

10. Before the crane is moved, the rigger shall determine that the load is high enough to 
clear all obstructions. All loose material shall be removed from the load before it is moved. 

11. No one shall be permitted to ride the hook, sling, or load, 
Safety Rules for Crane Operators 

1. Safety shall always be given first consideration in the operation of cranes. Operators 
shall constantly bear in mind that the safety of personnel on deck, as well as their own safety, 
depends upon the careful operation of the crane. Therefore, operators should be permitted to 
operate cranes only when they are physically fit. Any illness will be reported to the super- 
visor immediately. 

2. If any doubt exists concerning the safety of any situation or condition, the operator 
shall not move the crane or proceed with the lift until the unsafe condition is corrected and 
the supervisor has decided that the situation is safe. 

3. Operators shall familiarize themselves with the crane mechanism and its proper care, 
and with all operating safety rules. 

4. Both hands shall be used whenever ascending or descending the vertical crane ladder. 

5. Operators shall keep crane cabs clean at all times. 

6. Operators shall examine their crane daily for defective brakes, loose parts, or any 
condition which could make the crane unsafe. 

7. Whenever adjustments or repairs are necessary, the condition shall be reported to the 
supervisor immediately. 

8. At the beginning of each shift, operators shall test each limit switch by slowly raising 
the block until the limit switch opens the circuit. 

9. At least two full wraps of hoist cable shall be kept on the hoist drum. 
10. When leaving the crane, operators shall: 

a. Spot the crane at approved access. 

b. Raise all hooks to the upper limit switch. 

c. Move all controls to the "off" position. 

d. Lock the crane disconnect switch in the "off" position. 
Safe Lifting and Transportation of Heavy Loads 

1. The safe transportation by cranes of heavy loads depends upon the following three basic 
elements: 

a. The capacity and safe operating condition of the mechanical lifting equipment. 

b. The capacity and condition of the hitching devices and accessories used. 

c. The capabilities of the persons that operate, use, inspect, and repair the lifting 

equipment and hitching devices. 

2. The capacity of all hoisting equipment is posted and shall not be exceeded. 



160 OPERATIONAL AND EMERGENCY BILLS 

3. A safety factor is required for all lifting equipment. For example, the safety factor of 
wire rope is five, and the safe working load for any such equipment is one-fifth of the ultimate 
strength of the equipment when new. 

4. The crane shall be placed directly over the load being lifted to avoid sliding of the load 
and overstressing of the hoisting equipment. 

5. The load or hook shall at all times be raised high enough to clear all objects that are 
in the path of travel. 

6. Loads shall never be left suspended in the air while waiting or when the crane is left 
unattended. 

7. When lowering a load, the operator shall proceed carefully and make sure that the load 
is under control at all times. 

General Rules 

1. Cranes shall be operated only by an authorized crane operator. 

2. Only lifting materials and equipment which meet required specifications shall be used 
for the movement of any load. 

3. Crane operators and riggers shall operate as a team. Any disagreements concerning 
the safe handling of a load shall be referred to the rigger supervisor for a decision before 
proceeding with the lift. 

4. Only qualified personnel (riggers) shall be permitted to hook loads to a crane. 

5. Before any load is moved, it shall be the joint responsibility of both the rigger and the 
crane operator to be certain that all hitches have been safely made. 

6. Cranes and hitching equipment shall not be loaded beyond their rated capacity. 

7. Standard crane signals shall be accepted by the crane operator only from the rigger 
who is responsible for the lift. Only one rigger will give signals to the crane operator on each 
lift. In the event of an emergency , however, stop signals shall be accepted from anyone . 

8. It shall be the responsibility of the riggers and crane operators to keep personnel clear 
of all loads. 

9. No one shall be permitted to ride on the load, a hook, or a sling. 

10. Thorough housekeeping shall be maintained at all times on decks, in the crane cab, and 
on the catwalks. 

11. All personal injuries, no matter how slight, will be reported to the supervisor. In ad- 
dition, any accidents that cause damage to equipment or materials, or any irregularities ob- 
served in the operation of equipment, will be reported immediately. 

GENERAL CASUALTY INSTRUCTIONS 

1. In the event of a casualty resulting in an unbalance of atmospheric gases, all Sealab 
personnel will remain on the emergency air breathing system until the atmosphere is brought 
back into balance. 

2. In the event of any casualty, the bottom commander must insure that an adequate flow 
of information be provided topside. The topside commanders must be aware of current status 
and corrective procedures being instituted. 



OPERATIONAL AND EMERGENCY BILLS 161 

3. In general, the topside commanders will confer with the bottom commander whenever 
feasible; however, all orders issued by topside commanders will be considered mandatory. 

4. When in the opinion of the bottom commander that the Sealab structure must be evac- 
uated, he will order all personnel to the Personnel Transfer Capsule and so notify the topside 
commanders. The topside commanders will render the final decision as to decompress or 
hold, pending further evaluation of the situation. 

ACCIDENT OR ILLNESS EMERGENCY PROCEDURES 

1. In the event that the Senior Medical Monitor determines that the treatment of an ac- 
cident or illness is beyond the capabilities of the hospital corpsman, the subject can be brought 
to the surface in the Personnel Transfer Capsule. 

2. The Senior Medical Monitor may elect to send qualified personnel into the Sealab habi- 
tation for treatment of any casualty or call for the evacuation of the subject to the surface. 

3. In the event it becomes necessary to bring a subject to the surface in the Personnel 
Transfer Capsule, a surface- support diver shall be provided to serve as a tender. 

4. Subject and tender shall be transferred to the Deck Decompression Chamber for decom- 
pression and treatment, as determined by the Senior Medical Monitor. The Senior Medical 
Monitor may elect to return the subject to the Sealab habitat, in which case decompression 
would not proceed. 

LOSS OF PRESSURE OR FLOODING EMERGENCY PROCEDURES 

1. In the event of a pressure loss with flooding, it will be necessary to utilize damage- 
control materials and procedures. Immediately upon sounding the alarm, the bottom com- 
mander will designate one man to monitor communication system topside, with a continual 
flow of information, minimizing the need for topside to ask current status. 

2. Should efforts to correct the loss of pressure or to stem the flooding meet with failure, 
all subjects will proceed to the Personnel Transfer Capsule and be brought topside for transfer 
to the Deck Decompression Capsule. 

3. The Senior Medical Monitor and On-Site Commander will make the decision to decom- 
press or hold pressure, pending an evaluation of the habitability of the dwelling. 

4. An evacuation order issued by topside will be considered mandatory. 

FIRE 

1. With the concentration of oxygen levels established for Sealab H, it is unlikely that fire 
of significant proportions can occur. Severe electrical short circuit, however, could burn in- 
sulation and produce atmospheric contaminants. 

2. In the event a fire is detected, the oxygen supply system must be secured. 

3. If a fire alarm is sounded, the bottom commander will designate one subject to man the 
communication system to provide a flow of information topside. 

4. Those individuals designated by the bottom commander to fight fires will don the emer- 
gency air-breathing masks, and proceed to take corrective measures. All other subjects will 
evacuate to the Personnel Transfer Capsule to await further instructions. 

5. Orders to evacuate issued by topside will be considered mandatory. 



162 OPERATIONAL AND EMERGENCY BILLS 

LOSS OR ACCIDENT OUTSIDE THE SEALAB STRUCTURE 

1. In the event of a casualty outside the Sealab structure, the bottom commander shall 
sound the general recall alarm. All personnel outside the structure shall return immediately 
except the swim partner of the injured person or person lost from view. 

2. The bottom commander will then institute corrective measures which in his judgment 
appear to be most feasible and practicable. 

3. One man will monitor communications to provide a flow of information to the topside 
commander. 

SEALAB n ATMOSPHERIC CONTAMINATIONS 

Precautions 

The purpose of this instruction is to alert all personnel associated with Sealab type struc- 
tures to the importance of controlling atmospheric contamination, particularly those items 
which possess a toxicity hazard, toxicity hazard being the probability that injury may be caused 
by the manner in which a particular substance is used. 

In Sealab, inhalation of contaminated air is by far the most probable means by which toxic 
substances will gain entry into the body. This is of increasingly more importance when one 
considers that at normal atmospheric pressures, an individual under conditions of moderate 
exertion will breathe about 10 cubic meters (10,000 liters) of air in eight hours, thus some- 
what in the area of 30,000 liters per day. 

Although general ground rules have not been necessary for early manned undersea dwell- 
ings, relative to various items which may be introduced into the structure, this philosophy can 
no longer be considered valid. With increasing periods of prolonged submergence at greater 
sea pressures, and the increasing number of personnel and personnel logistic requirements, 
it is essential that careful consideration be given to minimizing toxicity hazards within any 
manned undersea dwelling or vehicles used in conjunction therewith. 

The capacity for removal of air contaminants which can be built into" manned undersea 
dwellings and small vehicles is extremely limited. In Sealab II, contamination control is 
limited to (a) carbon dioxide removal with lithium hydroxide and (b) activated charcoal for re- 
moval of some contaminants. In this regard, it must be remembered that charcoal will not 
remove all possible contaminants, and that, furthermore, it is capable of selective absorption. 
Selective absorption simply means that it may release one substance previously absorbed in 
exchange for another; therefore, it is possible that a toxic substance absorbed early in a bot- 
tomed dwelling may reappear later as this exchange process takes place. 

In manned undersea dwellings, paints and adhesives may be one of the largest offenders. 
It is suggested that principles which have been set down for nuclear submarines be adopted 
for future dwellings and vehicles. 

1. All major painting should be accomplished at least 30 days prior to manning, and any 
touch-up painting with oil-based paints be accomplished no less than 15 days prior. 

2. H it is necessary to paint interiors with less than 30 days remaining, water-base paints 
shall be used in lieu of chlorinated rubber-base paints. 

3. No painting shall be done within 72 hours of manning. 

Contaminants possessing a toxicity hazard may be introduced in many unsuspected ways, 
such as glues, hobby paints, some aerosol bombs, and cleaning solvents. 

In an effort to minimize the possibility of toxic substances being introduced into the at- 
mosphere of Sealab n, the following control procedure will be instituted. 



OPERATIONAL AND EMERGENCY BILLS 163 

1. All items of equipment, both professional and personal, shall be reviewed and approved 
for stowage and use aboard Sealab n. 

2. A careful log of all items intended for use within Sealab n shall be maintained by the 
Atmosphere Control Officer. 

3. Only the Senior Medical Monitor or the Atmosphere Control Officer may grant approval 
of items, and all items shall be logged. 

4. The log of items shall also list an approximate weight and storage location within the 
structure. This is necessary for accurate analysis of ballasting required for both towing and 
placement on the bottom at the chosen site. 

Captain Walter F. Mazzone, MSC, USN will maintain supervision of this program; there- 
fore all approvals granted by the Senior Medical Monitor, Captain George F. Bond, MC, USN, 
will by necessity have to be transmitted for logging the required data. 

Specific Conditions 

Sealab n is emplaced on the sea floor. The atmosphere can suffer contamination in many 
ways. One source is from electrical fires, which may generate smoke, ozone, and other ob- 
jectionable gases and odors. A second source could be spilled chemicals. 

Procedures 

In the event of atmospheric contamination, all subjects designated by the bottom commander 
will don the emergency air-breathing masks. All other subjects will proceed to the Personnel 
Transfer Capsule to await further instructions. 

Depending on the type of contamination, immediate measures will be taken to remove the 
source of contaminant. If the source is electrical, secure the main power. If the source is 
chemical, cover the source or wash down any spillage with a hose. 

Sealab' s atmosphere can be purged with fresh helium and oxygen from the spare bottles 
carried aboard. The racks carry ten bottles of helium, eleven bottles of oxygen and three 
bottles of premixed helium-oxygen gas. Fresh helium is introduced into the vent plenum. 
Fresh oxygen is introduced into the fan discharge duct. The fan should always be running when 
oxygen is introduced, to effect proper dilution of the gas, and to avoid a fire hazard. 

If all efforts to clear the atmosphere should fail, all subjects will proceed to the Personnel 
Transfer Capsule to be brought to the surface for transfer to the Deck Decompression Cham- 
ber, either to be decompressed or held at pressure pending an evaluation of the situation. The 
decision to decompress will be given by the Senior Medical Monitor and the Project Director. 

SEALAB H; ELECTRICAL POWER LOSS BILL 

In case of total power failure, take the following steps. 

1. Move all switches on main power panel to OFF. 

2. Notify support vessel to restore power. 

3. When either indicator lamp on panel glows, move corresponding power-supply switch 
to ON. (Mechanical interlock will prevent both NORMAL and ALTERNATE power supply 
switches from being on at same time). 

4. Move remaining switches, one at a time, to ON. (These are the load switches. No. 
1-4P-A to 1-4P-F). 



164 OPERATIONAL AND EMERGENCY BILLS 

5. Notify support vessel that power has been restored. 

To transfer power from alternate to normal supply (when indicator lamp on power panel 
shows normal power available). 

1. Move all switches on main power panel to OFF . 

2. Move normal power supply switch to ON . 

3. Move remaining switches, one at a time, to ON. (These are the load switches, No. 
1-4P-A to 1-4P-F.) 

4. Notify support vessel to switch off alternate power. Note: Normal power supply is 
from shore. Alternate power supply is from support vessel. 

STAGING VESSEL FOUL-WEATHER BILL 

1. Take hourly tensiometer readings on each leg and record. Note change. Tension should 
not exceed 50,000 lb. 

2. Request ComServRon One ATF to stand by. Alert Gear. If ATF not available, request 
Gear to stand by. 

3. Notify Commander, Naval Base, San Diego, of situation and alert for possible assistance. 

4. Secure all loose gear. 

5. Send all boats except one LCM to Quivira Basin, Mission Bay. 

6. Set up special 24-hour watch. 

7. Check position of "dumb waiter" line extending from Staging Vessel to Sealab II. 

8. Check position of Sealab n acoustically every hour or oftener. 

9. Check mooring legs for signs of dragging. 

10. If situation deteriorates, have ATF or Gear attach tow line, preferably nylon, and re- 
lieve strain or leg with the highest tension. 

11. In the event an anchor drags, shift pull of ATF to compensate. 

12. Maintain constant communication with all concerned. 

STAGING VESSEL MOOR SLIPPING BILL 

When weather and wave -prediction information indicate a hazardous condition is imminent, 
it will be necessary to move the staging vessel into the San Diego Harbor. These warnings 
should be received at least 24 hours in advance. The following procedure shall be followed for 
slipping the mooring: 

1. Request a ComServRon One ATF at site with at least one YTM or YTB tug. If ATF not 
available, request Gear. 

2. When tow line is attached to staging vessel, remove legs generally in inverse order of 
mooring. Buoy wire off with 59-in. spherical buoys or equivalent. Great care must be ex- 
ercised so that nothing is dropped on Sealab n and that all connections to Sealab II are broken. 

3. Take Staging Vessel into San Diego escorted by YTM or YTB tug. 

4. Send all boats to Quivira Basin, Mission Bay, LaJoUa. 



Section II 
AQUANAUTS 



I 



Chapter 24 
AOUANAUT BIOGRAPHIES 



G. P. Clapper 
Office of Naval Research 
Washington, D. C. 



Robert A Barth, Chief Quartermaster (DV), USN 
Team 2 

Chief Barth, 35, participated in Project GEN- 
ESIS and as an aquanaut in Sealab I. He is 
presently assigned to the U.S. Navy Mine 
Defense Laboratory, Panama City, Florida. 
He is married to the former Joyce Williams 
of Tampa, Florida and has two sons. 





Howard L. Buckner, Chief Steelworker (DV),USN, 
Team 2 

Chief Buckner, 36, served in Sealab I as a 
surface support diver. He is presently as- 
signed to the Experimental Diving Unit, 
Washington, D.C. He is married to the for- 
mer June Morris of Falls Church, Virginia, 
and has three daughters. 



167 



168 



AQUANAUT BIOGRAPHIES 



William J. Bunton, Team 3 

Mr. Bunton, 32, is an army veteran. He is 
presently an Experimental Test Mechanic at 
the Scripps Institution of Oceanography, La 
JoUa, California. He is married to the for- 
mer Betty LeClaire, of Detroit, Michigan, 
and has three daughters and two sons. 





Berry L. Cannon, Team 1 

Mr. Cannon, 30, is a Navy veteran. He is 
presently anElectronics Engineer at the U.S. 
Navy Mine Defense Laboratory, Panama City, 
Florida. He is married to the former Mary 
Louise Rutkowski of Chula Vista, California, 
and has two sons. 



CDR. M. Scott Carpenter, 
Teams 1 and 2 



USN, Team Leader, 



CDR. Carpenter, 40, has been assigned to the 
National Aeronautics and Space Administra- 
tion since April 1959. He piloted the three- 
orbit Mercury- Atlas 7 (AURORA 7) flight in 
May 1962. He participated in Sealab I as a 
topside assistant. He is married to the for- 
mer Rene Louise Price and has two sons and 
two daughters. 




AQUANAUT BIOGRAPHIES 



169 




Thomas A. Clarke, Team 3 

Mr. Clarke, 25, is the youngest Sealab n aq- 
uanaut. He is a graduate student in Marine 
Biology at the Scripps Institution of Oceanog- 
raphy, La JoUa, California. He is not mar- 
led. 



Billie L. Coffman, Torpedoman First class (SS) 
(DV), USN, Team 1 

Coffman, 36, has served with the Experimen- 
tal Diving Unit as an instructor. He is pres- 
ently assigned to the Submarine Medical 
Center, New London, Conn. He is married 
and has one daughter. 





Charles M. Coggeshall, Chief Gunner 's Mate (DV), 
USN, Team 3 

Chief Coggeshall, 35, is presently assigned 
to the U.S. Navy Mine Defense Laboratory, 
Panama City, Florida. He is married to the 
former Hazel Smith of South Norfolk Virginia 
and has two sons. 



170 



AQUANAUT BIOGRAPHIES 



Kenneth J. Conda, Torpedoman First Class (SS) 
(DV), USN, Team 2 

Conda, 33, is presently assigned to the U.S. 
Navy Submarine Medical Center , New London, 
Conn. He is married to the former Elsbeth 
Chace, of Somerset, Massachusetts, and has 
three daughters. 





George B. Bowling, Team 3 

Mr. Bowling, 39, is a Navy veteran. He is 
presently employed at the U.S. Navy Mine 
Befense Laboratory, Panama City, Florida, 
as a Research Physicist. He is married to 
the former Janet Bavis of Brondidge, Ala- 
bama, and has three daughters and one son. 



Wilbur H. Eaton, Gunner's Mate First Class (BV), USN 
Team 1 

Eaton, 39, participated in Sealab 1 as a surface sup- 
port diver. He is presently assigned to the U.S. 
Navy Mine Befense Laboratory, Panama City, Flor- 
ida. He is married to the former Annice Lee White 
of Plattsmouth, Nebraska, and has four daughters 
and two sons. 




AQUANAUT BIOGRAPHIES 



171 




Arthur O. Flechsig, Team 2 

Mr. Flechsig, 41, is chairman of the Scripps 
Diving Control Board. He is presently a 
Specialist Oceanographer at the Scripps In- 
stitution of Oceanography, La Jolla, Califor- 
nia. He is married to the former Phyllis 
Grant of Alamo, California, and has two sons 
and two daughters. 



Richard Grigg, Team 3 

Mr. Grigg, 28, is presently a graduate stu- 
dent in Marine Biology at the Scripps Insti- 
tution of Oceanography, La Jolla, California. 
He is married to the former Sandra Song and 
has one daughter. 





Glen L. Hey, Chief Hospital Corpsman (DV),USN, 
Team 2 





Chief Iley, 36, participated in Sealab I as a 
surface support diver. He is presently as- 
signed to the U.S. Naval Submarine Base, 
New London, Conn. He is married to the for- 
mer Edna P. McKay of Selma, Alabama and 
has two daughters. 



172 



AQUANAUT BIOGRAPHIES 



Wallace T. Jenkins, Team 2 

Mr. Jenkins, 30, is a Navy veteran. He is presently 
an Equipment Specialist at the U.S. Navy Mine De- 
fense Laboratory, Panama City, Florida. He is 
married to the former Sandra K. Sackman of Sedro 
Wooley, Washington, and has one son. 





Frederick J. Johler, Chief Engineman (DV),USN, 
Team 1 

Chief Johler, 40, participated in Sealab I as 
a surface support diver. He is presently as- 
signed to the U.S. Naval Submarine Base, 
New London, Conn. He is married to the for- 
mer Genevieve Blake of Buffalo, New York, 
and has two daughters. 



John J. Lyons, Engineman First Class (DV), USN, 
Team 3 

Lyons, 35, is presently assigned to the U.S. Navy 
Mine Defense Laboratory, Panama City, Florida. 
He is married to the former Shirley Miller of Chi- 
cago, 111., and has two sons and one daughter. 




AQUANAUT BIOGRAPHIES 



173 




William D. Meeks, Boatswains Mate First Class 
(DV),USN, Team 3 

Meaks, 34, is presently assigned to the Ex- 
perimental Diving Unit, Washington, D. C. 
He is married to the formerDoreen A. Conner 
of Wilmington, Delaware. 



LavernR. Meiskey, Chief Shipfitter (DV), USN, 
Team 3 

Chief Meiskey, 38, is presently assigned to 
the U.S. Navy Mine Defense Laboratory, 
Panama City, Florida. He is married to the 
former Dorothy Spiess of Spring Valley, 
Minnesota, and has one daughter. 





Earl "A" Murray, Team 1 

Mr. Murray, 38, is a Navy veteran. He is 
presently employed as a laboratory Assistant 
at the Scripps Institution of Oceanography, 
La JoUa, California. He has two daughters. 



174 



AQUANAUT BIOGRAPHIES 



John F. Reaves, Photographer First Class (DV), USN 
Team 2 

Reaves, 36, is presently assigned to the Pacific 
Mobile Photo Unit, NAS North Island, San Diego, 
California. He is married to the former Hilda Gray 
Dubberly of Jacksonville, Florida, and has two 

sons. 





Jay D. Skidmore, Chief Photographer (DV), USN, Team 1 

Chief Skidmore, 37, has participated in Project 
Nekton with the Bathyscaph Trieste. He is presently 
assigned to the Pacific Mobile Photo Unit, NAS 
North Island, San Diego, California. He is married 
to the former Lois Irene Wedeberg of Tacoma, 
Washington, and has one son and one daughter. 



Lt Robert E. Sonnenburg, 
and 3 



MC, USNR, Teams 1 



Lt Sonnenburg, 28, received his MD degree 
in 1962. He is presently assigned to the U.S. 
Navy Mine Defense Laboratory, Panama City, 
Florida. He is married to the former Patricia 
Ann Molin,San Diego, California, and has two 
daughters and one son. 




AQUANAUT BIOGRAPHIES 



175 




Robert C. Sheats, Master Chief Torpedoman (DV), 
USN, Team Leader, Team 3 

Chief Sheats, 50, participated in Sealab I as the 
Master Diver for surface support. He is pres- 
ently assigned to the U.S. Naval Torpedo Station, 
Keyport, Washington. He is married to the for- 
mer Alberta M. Bellerue of Poulsbo, Washington 
and has two sons. 



William H. Tolbert, Team 2 

Mr. Tolbert, 39, is presently employed as an Ocea- 
nographer at the U.S. Navy Mine Defense Labora- 
tory, Panama City, Florida. He is married to the 
former Betty Hammett of Vicksburg, Mississippi, 
and has two sons. 




176 



AQUANAUT BIOGRAPHIES 




Cyril J. Tuckfield, Chief Engineman (DV), USN, Team 1 

Chief Tuckfield, 44, participated in a submarine 
escape from 302 ft in 1959. He was a surface- 
support diver withSealab land is presently assigned 
to the U.S. Navy Mine Defense Laboratory, Panama 
City, Florida. He is married to the former Natalie 
Kryg, of Norwich, Connecticut. 



John M. Wells, Team 3 

Mr. Wells, 25, is presently employed as a 
Research Assistant at the Scripps Institution 
of Oceanography, La JoUa, California. He is 
not married. 



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!>aul A. Wells, Chief Mineman (DV), USN, Team 3 

Chief Wells, 38, is presently assigned to the U.S. 
Navy Mine Defense Laboratory, Panama City, Flor- 
ida. He is not married. 



Chapter 25 
AOUANAUT TRAINING 

M. S. Carpenter 

National Aeronautics and Space Administration 

Houston, Texas 

Training activities for crew members began April 1, 1965, in Panama City, Florida, 
nearly six months prior to the scheduled beginning of the underwater experiment. Classroom 
work included diving physiology and physics, detailed study of the Mk-VI semiclosed-circuit 
breathing apparatus which was used throughout the operation, underwater photography tech- 
niques and equipment, and familiarization with the hookah breathing apparatus, or "Arawak." 
In addition, many hours were spent becoming familiar with the Mk-1 SPU, or Swimmer Propul- 
sion Unit, and other auxiliary equipment such as test kits and gas charging pumps for the 
Mk-VI tanks. 

Underwater audio communication equipment and hand-held active and passive sonars were 
studied and operated, and many hours were spent in the diving locker designing and building 
equipment to support our operation, mix our gas, and store and ship our gear. Divers, by ne- 
cessity, are jacks-of-all-trades. 

Classroom familiarization with the Mk-VI breathing apparatus took one week. This time 
may seem excessive, but the Mk-VI is not the simple open-circuit scuba gear that most people 
associate with diving. Figure 77 shows the gas bottles and CO2 absorbent canister worn on 
the back. The control block, or pressure and flow regulator, is shown above the center canis- 
ter. Figure 78 shows the Mk-VI vest, which is made up of an inhalation bag on the diver's 
right side and an exhalation bag on his left. Hoses and a mouthpiece connect the two, and on 
the upper part of the exhalation bag is an exhaust valve which can be adjusted in the water by 
the diver. Adjustment of this valve regulates the amount of each exhalation that is exhausted, 
usually about one -third; that function is what qualifies the Mk-VI as a semiclosed-circuit 
breathing apparatus. The valve, used in conjunction with a bypass valve on the control block, 
also controls the degree of inflation of the breathing bags. This valve gives the diver some 
control of his buoyancy, which is very useful when he works at varying depths. 

Actual use of the equipment began in the swimming pool. After two one-hour sessions, we 
took to deep water, where we conducted the rest of the diving training. One day was spend div- 
ing in 30-ft water, four days in 60-ft water, five days in 100-ft water, all on N2 O2 mix, and 
another five days in 200-ft water on He02 mix. 

A good portion of our time was spent in becoming familiar with the physiological and psy- 
chological testing equipment and procedures. This orientation was necessary in its own right, 
of course, but it also provided good base-line performance data on each man. In addition, a 
day was spent at the Pensacola Naval Hospital with EEC, ECG, cardiopulmonary function, long- 
bone X-rays, and other physiological base-line studies. 

Unfortunately, the entire Sealab team was not available for training at the same time, which 
necessitated conducting all of the training at least twice. This difficulty, plus the lack of fast 
surface transportation to deep water, which was quite a way out, made for a not-too-efficient 
use of our time during this phase of our training. 

Throughout the three-month training period at Panama City, there was little opportunity to 
learn much about Sealab II herself, or the two decompression chambers we would be using. 
When the crew moved to Long Beach in July, we saw for the first time the nearly completed 

177 



178 



AQUANAUT TRAINING 





Fig. 77. Diver wearing Mk-VI 
semiclosed breathing apparatus 
showing gas bottles and COj ab- 
sorbent canister 



Fig. 78. Diver wearing Mk-VI 
semiclosed breathing apparatus 
showing inhalation and exhalation 
bags 



Sealab, and became busily engaged in learning her functions — valving procedures, mechanisms, 
etc. —and idiosyncrasies. Under the critical eyes of this crew, and those of Captain Walt 
Mazzone of the Submarine Medical Center and Joe Berkich of the Naval Ordnance Test Station 
(NOTS), many design changes were proposed and incorporated. Serious deficiencies in the de- 
sign and fabrication of both decompression chambers, which could have caused the loss of the 
entire crew of ten men, were uncovered and corrected. Testing procedures had to be devised, 
and operating instructions had to be drawn up, all by trial and error, before training in the 
proper use of the PTC and DDC could be conducted. Throughout this period, much time was 
spent doing the labor required to get our home ready for the sea floor. The time might have 
been spent better in study of procedures, blueprints, system operation, and continued on-site 
deep-water exposure with the Mk-VI. This, however, would have required more men, more 
time, and, of course, more money than we were allotted. 

Throughout this four-month training period, each day was started with 30 to 40 minutes of 
compulsory physical training in the form of running and calisthenics. 



The training schedule and a breakdown of the Mk-VI portion of the schedule are shown in 
Tables 4 and 5, respectively. 



AQUANAUT TRAINING 



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chapter 26 
AOUANAUT DAILY ROUTINES 

M. S. Carpenter 

National Aeronautics and Space Administration 

Houston, Texas 

After the lowering operation was completed and the condition of the lab had been monitored 
for approximately 36 hours, the occupancy by the first crew was commenced. The first team 
of two divers opened and inspected the Sealab; the second team of two divers opened and in- 
spected the personnel transfer capsule, which rested on the bottom within 20 ft of the Sealab 
entrance hatch. When the satisfactory condition of both had been reported topside, the remain- 
ing three two-man teams swam down to the lab, accomplishing as much of the necessary work 
outside the lab as time would allow. The rest of the first day was spent unstowing and rear- 
ranging the equipment inside the lab and doing the essential work outside the lab. This work 
consisted mainly of connecting the fresh-water lines, which was done with relatively little 
trouble except for some valve -management problems on the lab, and connecting the drain 
hoses. This operation presented some unforeseen problems, because the lines were buoyant 
and had to be weighted in order to prevent gas leakage from the lab. 

The first tasks on the bottom involved unsecuring the rest of the equipment that had been 
lashed down for the tow from Long Beach, and restowing it so that there was room enough for 
ten men. The safety anchor line, sewage lines, diving-light leads, benthic lab lines, Arawak 
hoses, and guide lines had to be connected. All drain plugs, external and internal port covers, 
and lowering lines had to be removed and stowed. 

Once the lab was reasonably habitable, all of the spare time in the water was devoted to the 
scientific programs and equipment evaluations. These activities included the erection of the 
strength-test platform and associated torque wrenches, the two-hand coordinator, the current 
meter, underwater weather station and sound range, visual acuity range, stationary target ar- 
ray, water clarity meter, pneumofathometer, fish cages, homing beacons, compass rose, ex- 
ternal TV cameras, bioluminescence meter, foam and salvage project equipment, bottom cur- 
rent trailers, underwater studgun equipment, photo and diving lights, bathythermograph, wave 
gage, and antitorque underwater tool test equipment. 

Before and after each dive, strength and manual dexterity tests were performed in the wa- 
ter with the aid of equipment designed specifically for this purpose. Another task that required 
quite a bit of in-the-water time was that of straightening the outside Arawak hoses, which con- 
tinually fouled and kinked. This job had to be accomplished almost daily. Resupply through 
the system of pots and baskets also consumed altogether too much of divers' time. 

During the third team's tenure on the bottom, the storm of activity centered around re- 
supply abated somewhat because of the installation of a high-pressure helium-mix line in the 
lab. This line, supplied by pumps on the surface ship, permitted recharging of the Mk-Vl bot- 
tles in the lab instead of sending them topside for refilling. It not only reduced the workload 
on the men, but also was kinder to the equipment. 

A watch schedule had been set up prior to the first dive, and it went into effect immediately 
after the lab was occupied. The schedule which appears in Table 6 provided two men on watch 
at all times during the working hours, and one-man watch sections during the sleeping hours.' 
The responsibilities of the working-hours watch section included keeping the log, handling 
communications with topside, preparing and cleaning up after the meals, and staging the divers. 
It was more a rule than an exception that these tasks had to be performed concurrently; and 

182 



AQUANAUT DAILY ROUTINES 



183 



frequently the duty section found it necessary to stage divers, keep the log, cook, communicate, 
and clean up all at the same time. Needless to say, without the cooperation of the entire crew 
through the entire working day, the mission of the lab just could not have been carried out. 

Table 6 
SEALAB II WATCH SCHEDULE 



Time 


Mon 


Tue 


Wed 


Thu 


Fri 


Sat 


Sun 


Mon 


Tue 


Wed 


0600 

to 

1100 


1 


3 


5 


2 ■ 


4 


1 


3 


5 


2 


4 


1100 

to 

1600 


2 


4 


1 


3 


5 


2 


4 


1 


3 


5 


1600 

to 

2100 


3 


5 


2 


4 


1 


3 


5 


2 


4 


1 


2100 

to 

2400 


4A 


lA 


3A 


5A 


2A 


4B 


IB 


3B 


5B 


2B 


0000 

to 

0300 


4B 


IB 


3B 


5B 


2B 


4A 


lA 


3A 


5A 


2A 


0300 

to 
0600 


5A 


2A 


4A 


lA 


3A 


5B 


2B 


4B 


IB 


3B 


Super- 
numer- 
ary 


5B 


2B 


4B 


IB 


3B 


5A 


2A 


4A 


lA 


3A 



Buddy Team and Individual Number Assignments 



Carpenter lA 

Eaton IB 

Tuckfield 2A 

Cannon 2B 



Team 1 

Team 2 

Johler 5A 
Clarke 5B 



Sonnenburg 3A 
C off man 3B 

Murray 4A 

Skidmore 4B 

Team 5' 



Team 3 



Team 4 



The sleeping-hours watch section, although composed of only one man, was not nearly so 
hectic. There was time to engage in a little idle chatter with the surface, make the daily re- 
port of our activities to topside, finish off the log, and set up four or six Mk-VI breathing rigs 
for the next day's sorties. 

The daily schedules changed each day, as did the "Pians-of-the-Day" (P.O.D.), until a 
smooth operation evolved out of the first trial-and-error week of activity on the bottom. The 
accompanying list shows the Plan of the Day in the form which was adopted after a week or ten 
days of evolution. The Sunday P.O.D. continued with the same watch schedule, but there was 
no scheduled breakfast; each man fixed his own brunch, and diving was at the discretion of the 
individual teams. The evening meal was prepared by the duty section as usual. 



184 AQUANAUT DAILY ROUTINES 

Activities not specifically covered by the Plan of the Day went as follows: 

SEALAB n 

Monday P.O.D. 24 20 Sept. 1965 

Duty Diving Teams 

06-11 Barth - Buckner 1. Jenkins - Tolbert* 

11-16 Reaves - Jenkins 2. Dowling* - Carpenter 

16-21 Conda - Dowling 3. Barth* - Buckner 

21-24 Flechsig 4. Buckner - Conda* 

00-03 Tolbert 5. Reaves* out with each 

team at his discretion 
03-06 Iley for photos 

Super Carpenter * Standby Diver 

DIVING JOBS 

1. Bioluminescence Meter Installation 

2. Compass Rose Orientation 

3. Retrieve Bathythermograph 

4. Check Current Meter 

5. Release Bottom Current Trailers 

6. Bring in Two-Hand Coordinator 

7. PQS-1 Evaluation 

8. Locate Way Station 

9. Excursion to 266 ft — ten minutes 

10. Measure Lab Heading 

11. Logistics 

12. Lengthen Pneumofathometer 

13. Logistics 

14. Measure Sealab Settling 

15. Hook up PTC Steady Light 

16. Rig Diving Lights 

17. Sound Range Test at 1430 



AQUANAUT DAILY ROUTINES 185 

TEAM ASSIGNMENTS 

Team 1. (A) 1, 2, 3, 4, 17, Prepost Strength and Touch Sensitivity 

Tests 

Team 2. (E) 5, 6, Clean up Team 1, Prepost Touch Sensitivity and A 
No. 2 (Carpenter) No. 5 (Dowling) 

Team 3. (M) 9, 10, 11, Prepost Strength Test 

Team 4. (E) 15, 16, 17, 14, 13, Prepost A No. 1 (Buckner) No. 4 (Conda) 

A = Arawak M = Mk-VI E = Either 

NOTES 

1. BIB and BOB modifications 5. Camera fitting 

2. Change pulley and camera 6. Parts to A's 
mount stowage 7, Sound test 

3. Condensate records 8. Barth - Envelopes 

4. LiOH cans 9. Gov. Brown Talk 

The two-man 0600-1100 watch section was awakened at 0545, and the preparation of break- 
fast was begun. Reveille was held at 0700. Breakfast was over, and the cleaning up was usually 
completed, by 0800, when morning quarters was held. Prior to breakfast, each man recorded 
his weight on a chart provided for that purpose. Other physiological studies were done at this 
time, i.e., blood and urine sampling. 

During quarters, the P.O.D. was discussed, and often changed because of conflicting activ- 
ities on the surface, and occasionally because of headaches or other temporary indispositions 
of the crew members. As far as I know, no man dived if he did not feel up to the job. 

An effort was made to have each man dive at least once with each of the other men in his 
crew during his two-week stay on the bottom, although this was not always possible because of 
the nature of some of the scientific work that was done. 

The close quarters that comprised our diving station made it very difficult to get more 
than one team of divers in the water at one time. It often required ten hours to get five two- 
men teams in the water during the day, even though the average duration of our dives was in 
the neighborhood of 45 minutes. In addition, divers were always called back to the lab during 
the lowering of equipment or supplies from the surface and also during the noon meal hour. 

The afternoon work period was similar to the morning work period, and was usually com- 
pleted by 1800, with the exception of resupply activities which often required the services of a 
suited Arawak diver until much later in the evening. 

Daily repair activities usually took place after the evening meal, as did continued physio- 
logical and psychological testing. The diving lights burned out much too frequently and had to 
be brought in, repaired, and reinstalled. An Arawak pump required disassembly on two sepa- 
rate occasions; dehumidifiers needed modification to allow proper drainage, as did the central 
conning tower area, the scupper drains, and the sink and shower drains. This work was neces- 
sitated by the list and pitch of the lab, which was just outside the limits of the slope of all our 
drain lines. 

Commercial TV was available to the crew each night, but usually everyone was too busy to 
pay much attention to it. A phone line to the shore was also available; but, with few exceptions, 
it was not utilized very much for outgoing calls. 



186 AQUANAUT DAILY ROUTINES 

Drying the Mk-VI hoses and vests was a daily activity that usually did not start until the 
evening hours, but continued throughout the night. A commercially available ladies hair dryer 
was taped to the Arawak pump support framework and ducted with rubber hoses in such a fash- 
ion that three Mk-VI vests could be dried at the same time. The system worked very well, but 
was difficult to set up, and it needs some refinement before the next experiment. A greater 
air -flow rate is one requirement. 

In general, activities associated with preparing for each dive, repair of equipment, and 
logistics required too much of the Sealab divers' time. Although we spent an unprecedented 
amount of time in the water, the support activity presented a work load far out of proportion to 
the useful work done. The long hours and hard work were cheerfully accepted by these crews, 
but when this type of duty becomes more prolonged and more commonplace and the motivation 
provided by the experimental situation is no longer present, crew efficiency and morale will 
flag. Better human engineering of all the equipment will be a most effective means for reduc- 
ing the amount of time spent in diver support. 

The days on the bottom in Sealab II often consisted of 20 hours of steady work. There is, 
however, no reason not to believe that with the refinement of procedures and equipment, and a 
crew of the same calibre, we will be able in the future to accomplish much more useful work 
in much less time, and have a little left over for recreation and a more nearly normal way of 
life underwater. 



Chapter 27 
FUTURE SELECTION OF AOUANAUTS 



R. Radloff 

Naval Medical Research Institute 

Bethesda, Maryland 

PURPOSE 

The purpose of this chapter is to describe and explain some of the measures which may be 
used in selecting men for future operations similar to Sealab. The information used in this 
analysis is based on correlations between background information and measures of perform- 
ance and adjustment on men who participated in Sealab II. It should be emphasized that this 
presentation represents the barest beginning of a process of developing a uniform set of pro- 
cedures and instruments to be used in selecting future aquanauts. Not only were materials and 
methods of measurement used in Sealab II limited, but also the analysis and interpretation of 
even those limited materials is incomplete at this time. However, it has been said that a jour- 
ney of a thousand miles begins with a single step. This discussion represents, hopefully, at 
least a few solid strides toward a soundly based system of crew selection. 

DEVELOPING A SELECTION METHOD 

The basic aim of this section is to predict performance and adaptation in Sealab. Both 
predictors and criteria are multiple. Ten criteria have been derived. Four are intended to be 
indices of work. Examples are diving time and number of sorties. Four of the criteria can be 
loosely called measures of adjustment. Examples are satisfaction with meals and quality of 
sleep. Men in each crew were given quantitative ratings by their crew leaders. Finally, each 
man was asked to name the men he would most like to have as crew mates in future Sealabs. 
These postchoices have been used as a criterion variable. 

Only a few of the many possible predictor variables have been chosen for this presenta- 
tion. They are of two types. First are a set of demographic variables, such as age, diving ex- 
perience, and education. Second, the AUport-Vernon-Lindzey Study of Values has been selected 
for analysis. The scale of values is probably the easiest to understand and interpret of the 
standard measuring instruments administered to the aquanauts. 

Only a few predictors have been used, for a variety of reasons. First, the ones chosen 
were judged to be among the best in terms of their ease of interpretation and understanding. 
Second, it will require some time, even for a computer, to reproduce all the intercorrelations. 
Third, even if the thousands of intercorrelations of predictors and criteria were available, too 
much time and space would be required to analyze and interpret them meaningfully for this re- 
port. In fact, more predictor variables have been correlated with the criteria than those pre- 
sented in this report. Those not included either did not correlate significantly with the criteria, 
or the associations were difficult to interpret and explain. 

This report, therefore, is not the full story on crew selection. Even when all the data 
available on Sealab aquanauts have been analyzed, however, only a small beginning will have 
been made. What is meant here can best be illustrated by citing the philosophy and experience 
of the Peace Corps in its outstanding program of selecting overseas personnel. Peace Corps 
Director Sargent Shriver, in discussing selection, said, "... a selection process must depend 
on a conglomeration of considerations. No one test, nor any one procedure can be counted 
upon." Dr. Abraham Carp, Peace Corps Selection Director, further stated, "The selection of 

187 



188 FUTURE SELECTION OF AQUANAUTS 

people is a young science. No one selection tool even begins to approach perfection. That is 
why Peace Corps selection is deliberately structured to bring to bear many different selection 
tools." ". . . no one element of this process is determinative but each makes a definite and 
distinctive contribution to the process." Thus the tests or predictors used on this one group of 
aquanauts cannot be used, by themselves alone, to select future crews of undersea dwellers. 
The results of this study will have to be crossvalidated in similar situations. However, a be- 
ginning has been made. Because information was collected on the crews of Sealab II, predic- 
tors and criteria are available. More important, information is available on this group so that 
comparisons with other groups are possible. 



CRITERION VARIABLES 
General Comments 

No single criterion could describe adequately the behavior of the men in Sealab. Ten cri- 
terion variables will be used in this report. More are available for later reports. They have 
not been included here, since many of them require involved and complex treatments of data. 
It is recognized that any criterion which is used is biased in the sense that it tends to favor the 
performance or behavior of some men over that of others. However, it should be pointed out 
that the purpose of this report is not to rate the men as such but to rate characteristics of men, 
with the purpose of producing a profile of characteristics which might predict favorable adjust- 
ment and performance in a Sealab-type environment. 

Each of the criteria will be defined and their shortcomings and advantages or biases indi- 
cated. Most of these criteria have been corrected for within-team differences. That is, each 
man's performance is rated only against members of his own ten-man team for purposes of 
determining his score on each variable. This is done because conditions varied considerably 
from team to team. For example, Teams 2 and 3 had the advantage of experience over Team 1. 
Also, Team 3 had the advantage of a charging hose for the Mk-VI bottles, which allowed them 
to spend considerably more time in the water than either Teams 1 or 2. Finally, there appear, 
from the diving log, to have been differences among teams in recording various aspects of 
work. Using within-team comparisons does not, however, preclude the comparison of men 
between teams. This is because once standard scores within teams are assigned, these scores 
can then be used to compare a man from one team with a man from another. 

Types of Criterion Variables 

Three types of criterion variables have been used here. One type is called the "work" 
criterion variable. There are four of these. A second is called the "general adjustment" cri- 
terion variable. There are also four of these. Two variables do not fit into either category; 
these are leader ratings and peer choices. 

Definitions of Criterion Variables 

Diving Time— A Work Criterion — Diving time was checked against the diving log kept in 
Sealab. While there were a few missing times in this document, it was remarkably complete 
and accurate considering the hectic pace and the multiple duties of men in Sealab and the fact 
that the log was kept by 28 separate individuals. It should be pointed out that diving time tends 
to favor members of Team 3; however, as previously noted, a correction is made for this bias 
by rating men within teams. A bias which cannot be corrected is the discrimination against 
men with special tasks which required them to work inside Sealab rather than out in the water. 
However, there are other variables on which these men are probably favored, and an overall 
criterion will probably give an accurate picture. 

Number of Sorties— A Work Criterion — The number of sorties was also checked against 
the diving log. There appears to have been some change in the definition of a sortie from team 
to team. Also, some excursions into the water for minor tasks, such as taking out the garbage 
or bringing in pots from the surface, were not given numbers and defined as sorties. Since 



FUTURE SELECTION OF AQUANAUTS 189 

there appeared to be very little consistency on this matter in counting sorties, each definable 
departure of a man from the capsule was counted as a sortie regardless of whether it had been 
given a number in the official log. On many, perhaps the majority of sorties, men returned to 
Sealab for brief periods. If the same partners went out after returning to Sealab and if they 
did not stay in longer than 10 minutes, or if the sortie was recorded as only one sortie in the 
diving log, men were not given credit for a second sortie after returning to Sealab. However, 
if a man went out with a new partner after returning to Sealab, or if his original departure had 
not been counted as a sortie and the time in Sealab was greater than 10 minutes, he was cred- 
ited with an additional sortie when he left a second or more than a second time. Sorties were 
not counted as a number but rather as a ratio of the number of sorties to the number of days 
dived; for example, if a man dived on 12 days and was out on 18 separate sorties, he would have 
a ratio of 1.50. If another man dived on only 10 days and was out on 15 separate sorties, he 
would also have a ratio of 1.50. This system was used because many of the men, for a variety 
of reasons, did not dive every day. In many cases, this was due to scorpion stings, headaches, 
skin rashes, and the like. Since lesser diving time due to such incidents is recorded in diving 
time as a variable, it was felt that the number of sorties as a variable would be quite redundant 
if no correction were made for such incidents. Therefore, the denominator for the ratio of 
number of sorties was the total number of days a man entered the water. As with diving time, 
number of sorties was also computed within teams. 

Increase or Decrease in Diving Time— A Work Criterion — This variable compares the 
time a man spent in the water during the second week with the time spent in the water during 
the first week. It is somewhat different from diving time and number of sorties. Regardless 
of how long a man was in the water, it would have been possible for him to increase or decrease 
his time from week one to week two. Such an increase or decrease can probably best be con- 
sidered as a measure of stamina, motivation, or both. In computing this variable, an average 
dive time per day was used. Diving times from Monday through Saturday only were used, since 
Sunday was an unusual day in Sealab. As in figuring the sortie ratio, only the number of days 
on which a man dived was used as a denominator in this variable. For example, if a man dived 
on only four days during the six-day week and was inactive the other two days because of ill 
health, the number 4 was used in the denominator for calculating his average dive time for the 
week. For nearly all men, the amount of time spent in the water increased in week two com- 
pared to week one. Scores were computed within teams. 

Number of Human Performance Tasks Completed— A Work Criterion — This variable is a 
ratio of the number of tasks completed on the human performance program per sortie. For 
most dives, most men were asked, if time was available, to perform one or more tasks in the 
human-performance program. In many cases, other things took precedence over these tasks. 
From debrief interviews, however, many of the men were completely candid and said that they 
were just too cold, too tired, or didn't feel like doing a particular task before they came back 
into the capsule. Therefore, performance of these tasks appeared to be somewhat dependent 
on motivation. 

Outside Telephone Calls— An Adjustment Criterion — The number of outside telephone calls 
made by a man is considered a measure of overall adjustment. The notion behind such consid- 
eration is that if a man were completely satisfied with his lot in Sealab he would have very little 
need to have contact with the outside world. Therefore, he should make very few telephone 
calls. This variable was also adjusted for between-team differences, since the capability of 
making outside calls was not available for approximately half the stay of Team 1. Teams 2 
and 3 were able to make outside calls during their entire stays. However, there is another 
reason for correction within teams. Only one telephone was available; if one man were occupy- 
ing the phone, it would be impossible for another man to make a call at that time. 

Meal Satisfaction— An Adjustment Criterion — Each day each aquanaut completed a daily- 
activities checklist. On this form he indicated whether or not he had eaten each of the meals 
during the day and, on a quantified scale, how much he liked the meal. These meal ratings 
were summed across each man for all meals eaten, and the mean reported satisfaction is the 
score used for this variable. These scores were computed within teams also, since there were 
differences in the types and methods of preparation of meals between teams. It should be 
noted that this is a self-report variable. With all such variables, there is always the possibility 



190 FUTURE SELECTION OF AQUANAUTS 

that some men may report what they feel is the desired reaction or the appropriate reaction 
rather than their true reaction. 

Quality of Sleep— An Adjustment Criterion — Also on the daily-activities checklist each 
man was asked to indicate how well he had slept the night before. These reactions were given 
on a five-point scale. Scores were computed within teams, since there were apparently some 
differences in the atmosphere in the capsule between teams which may have affected quality of 
sleep. It should be noted that this is another self-report variable. 

Times Up During the Night— An Adjustment Criterion —A fourth indicator of overall ad- 
justment, closely correlated with quality of sleep, was the number of times a man got up dur- 
ing the night. This variable was corrected for between-team differences for the same reason 
as the quality-of-sleep variable. It is, of course, a self-report variable. 

Leader Rating — The team leaders were asked to rate the performance of each man in their 
teams at the end of the Sealab experiment. These ratings were given on two 4-point scales. 
On one scale, the leaders were asked to rate the men on overall performance as divers. On 
the second scale, they were asked to rate the willingness of the man to perform his share or 
more of common work. The results of these two scales were summated to produce one leader- 
rating score. For purposes of analysis, the two leaders themselves were given the top ratings 
available on this variable. No corrections were made for between-team differences on leader 
ratings. One man who was rated by both leaders was given a score which was the average of 
the two leader-rating scores. 

Teammate Choices —At the end of his 15 days in Sealab, each man was asked to name the 
five men he would most like to have with him on a future hypothetical Sealab submersion. In- 
structions were that men could be chosen from among the 28 Sealab aquanauts. For this vari- 
able, each man was given a score determined in the following way; if he was chosen first by a 
teammate, he was given 5 points; if chosen second, 4 points; if chosen third, 3 points; if chosen 
fourth, 2 points; and if chosen fifth, 1 point. If he was not chosen, of course he was given no 
points. The weighted choices were then added for each man, and this score was used in deter- 
mining the favorability of teammates toward each man. It should be noted that within-team 
choices increased from a pre- to postmeasure for all three teams. However, the choices 
within teams were by no means unanimous, and there were still a large number of choices 
across teams. 

PREDICTOR VARIABLES 

As indicated above, only a limited number of predictor variables have been used for this 
preliminary analysis. Only two types of predictor variables will be reported here. They are 
demographic characteristics and basic values as measured by the AUport-Vernon-Lindzey 
Study of Values 

Demographic Characteristics 

Six variables of this type were used. They are age, diving experience, education, birth 
order, family mobility, and size of home town. At first glance this may seem to be an odd mix 
of variables; however, they were not chosen capriciously, and an explanation of their choice 
may be in order. 

First of all, demographic characteristics have one appealing advantage over such variables 
as interests, attitudes, personality, and the like for the purpose of developing criteria. The ad- 
vantage is that they are objective and therefore highly reliable. A problem with measures of 
interests and attitudes is that they are frequently of low reliability. This is particularly true 
if a man knows that such measures will be used as selection criteria. In such circumstances 
he may say to himself, "How will it affect my chances of being selected if I answer this ques- 
tion 'yss' vs 'no' or 'strongly agree' vs 'moderately agree'," and answer accordingly. Even 
without such conscious or unconscious biasing influences there is the problem that some men 
are just more candid about themselves than others, or that they know their own thoughts and 



FUTURE SELECTION OF AQUANAUTS 191 

feelings better. Distortions of answers are possible but far less likely to questions concerning 
objective demographic characteristics than they are for variables of the interest-and-attitude 
variety. 

A second advantage of demographic characteristics is that they are easy to obtain and ana- 
lyze. A few simple and unobjectionable questions can frequently supply as much information 
as a long battery of less objective questions, or possibly more. Once their utility as selection 
predictors has been established, demographic characteristics can be used without a complex 
scoring or analysis process. 

Finally, demographic characteristics have useful predictors in other situations where men 
have been exposed to stressful environments. A brief discussion of some of the possible rela- 
tions among the demographic variables and performance will indicate why these particular 
variables were chosen. Probably no discussion of age and experience are necessary in this 
regard. It is quite reasonable to expect that an older and more experienced man will cope 
better with a stressful situation than will a younger and less experienced man. On the other 
hand, there is no reason to expect that education per se would have an appreciable relation to 
performance in Sealab. However, there was a considerable range in years of education among 
the aquanauts, and the civilian and military subgroups were quite different in education, and in 
the functions they performed as well. This fact would tend to wash out any correlation between 
education and performance in the group as a whole. However, if amount of education is related 
to how well a man does his job or to his ability to adjust to others in the group, there could be 
a correlation between education and criteria within either the military or civilian subgroup. 

Birth order, size of home town, and family mobility are variables which are similar to 
each other, in that each one can be significantly related to the type of person one has become. 
It has long been known in psychology that whether a person was an only child or first born, or 
whether he had older siblings, had profound effects on his personality and behavior. However, 
the nature of these effects has been confused and muddled for an equally long period. In recent 
years, studies have accumulated which indicate that first and only borns are more reactive to 
other people and may be more dependent upon them, particularly in stressful situations. The 
findings regarding birth order are not at all clear at this time, but the variable has been found 
to be of great significance in a variety of situations involving social behavior and stress. Per- 
haps the finding of most relevance for present purposes is the fact that later-born men were 
significantly better fighter pilots during the Korean War as measured by the number of enemy 
planes they destroyed. Similar data are not available for size of home town and family mobil- 
ity. These variables were included because of the reasonable presumption that men who had 
been raised in a small town or whose families had not moved while they were growing up would 
be different from men who were raised in the city or whose families moved frequently. It would 
be an unnecessary digression to present the speculations concerning the possible relationship 
between these variables and performance and adjustment in Sealab. 

The other type of measure used in this analysis is the "Study of Values." This series of 
scales measures the basic value orientation of a person. It is perhaps the most widely used 
measuring instrument of its type. There are six basic value orientations measured by this 
form; they are theoretical or scientific, economic, aesthetic, social, political, and religious. 
By answering a series of questions, a person indicates the relative importance of each of these 
value orientations for himself. For example, a person scoring high on the theoretical scale is 
interested in studying the world around him, of acquiring knowledge for its own sake. A person 
scoring high on the political scale is interested in activities in which he is in control of or di- 
recting other persons. In contrast to the specific objective information represented by the 
demographic variables, the study of values provides data which is general and subjective. 
Thus, in a sense, considering types of information available about a man, this analysis employs 
data from two ends of a continuum ranging from specific and objective on one end to general 
and subjective on the other. 

Intercorrelations of Demographic and Criterion Variables 

Correlations between demographic and criterion variables are presented in Table 7. The 
symbols in the table indicate the degree of association. No symbol means, of course, that the 
correlation is not significant. 



192 



FUTURE SELECTION OF AQUANAUTS 



Table 7 
INTERCORRELATIONS OF DEMOGRAPHIC AND CRITERION VARIABLES 



Criterion 


Age 


Diving 
Expe- 
rience 


Educa- 
tion 


Birth 
Order 


Family 
Mobility 


Size 

of 

Home 

Town 


Number of Sorties 


0.32t 


0.43t 


-0.19 


0.50§ 


-0.15 


-0.33t 


Diving Time 


0.02 


0.12 


-0.05 


0.47 § 


-0.28 


-0.49 


Human Perform- 
ance Tasks 


0.09 


0.15 


-0.15 


0.20 


-0.17 


-0.18 


Change in 

Diving Time 


-0.14 


0.12 


-0.26 


-0.10 


-0.11 


0.14 


Outside Tele- 
phone Calls" 


0.31 


0.06 


-0.14 


0.42t 


-0.15 


-0.39 


Meal Satisfaction 


0.30 


0.13 


-0.08 


0.04 


-0.15 


-0.21 


Quality of Sleep 


0.02 


0.04 


0.05 


0.09 


-0.15 


-0.12 


Up During 
the Night* 


-0.12 


-0.01 


0.13 


-0.05 


-0.06 


-0.33t 


Teammate Choice 


0.61§ 


0.52§ 


-0.29 


0.18 


0.42t 


-0.16 


Leader Rating 


0.38* 


0.23 


-0.16 


0.27 


0.09 


-0.34t 



''"Fewer considered better. 
Tp 0.10, slightly correlated. 
+p 0.05, moderately correlated. 
§p 0.01, highly correlated. 



The predictors most frequently and highly correlated with the criteria are age, diving ex- 
perience, birth order, and size of home town. Family mobility is correlated with only one of 
the criteria, and education is correlated with none. Among the criteria, number of sorties, 
diving time, outside telephone calls, teammate choice, and leader rating each have two or more 
significant correlations with predictors. It is interesting to note that of the three self-report 
criteria (meal satisfaction, quality of sleep, and times up during the night) only one is corre- 
lated, and that one only slightly, with only one of the predictors. Number of human-performance 
tasks completed and changes in diving time are not correlated with any of the predictors. 
There are three facts of interest in Table 7 which lend particular weight to the results. First 
is the fact that the better or harder criteria are the ones correlated with the predictors. Sec- 
ond is the large number of significant correlations. Third is the internal consistency of the 
results. Each of these points warrants a brief elaboration. 

By better or harder criteria is meant those which are based on more data rather than less, 
objective data rather than subjective, and direct rather than indirect measures. Thus, number 
of outside telephone calls is a harder measure of adjustment than are meal satisfaction, quality 
of sleep, and times up during the night, because it is an objective and factual record rather 
than a subjective self-report. The difference here is in rating a man by what he does rather 
than by what he says. Number of human-performance tasks completed is a poorer measure of 
work performance than number of sorties, simply because there were so many fewer human- 
performance tasks performed than there were sorties. Change in diving time is a complex and 
derived measure compared to the straight record of diving time. The variable of teammate 
choice involves a tremendous amount of data, since in reality each man was rated 27 separate 
times, since he either was or was not chosen by his fellow aquanauts. The leader ratings can 



FUTURE SELECTION OF AQUANAUTS 193 

be considered semiobjective, since they were made by hard-headed, experienced men using 
quantitative scales. 

Using, then, the five harder or better criterion variables and the five predictor variables — 
eliminating education, since the civilian-Navy differences would tend to restrict correlations — 
we have a 5 x 5 matrix. Within this 5x5 matrix there are 10 out of a possible 25 significant 
correlations, with three more of borderline significance. By chance, we would expect only one 
significant correlation from this matrix. The demographic and criterion variables have an 
extremely high number of correlations. 

Finally, there is the fact of internal consistency. Looking down the columns of Table 7 it 
can be seen that the signs of all significant correlations within each column are the same. 
That is, age is always positively correlated with the criteria when the correlations are signifi- 
cant, and size of home town is always negatively correlated, and so on. 

We can conclude from Table 7 that the more successful aquanaut in Sealab II was older, 
had more diving experience, was more likely to have been later born, and was raised in a 
smaller-sized town than was the less successful aquanaut. By success is meant that he went 
on a greater number of sorties, spent more time in the water, was chosen as a teammate more 
often by his peers, his performance was rated higher by his leader, and he appears to have 
been more satisfied with life in Sealab, as indicated by the fact that he made fewer outside 
telephone calls. A word of caution is in order in considering these results. These correla- 
tions are group tendencies only. They cannot be applied to individual aquanauts, excluding 
other considerations. There may well have been first-born, young men, with relatively little 
diving experience, not raised in small towns, who were among the best divers in Sealab. If 
this is true, then what do these results mean? Just how these predictors should enter into a 
selection process will be discussed after additional results are presented. 

Correlations Between Allport-Vernon-Lindzey Values and Criteria 

The Allport-Vernon-Lindzey Study of Values has six value scales. Ten criterion variables 
were used. In the 6 x 10 matrix of values by criteria there was only one significant correlation. 
Since the appearance of one significant correlation could be a chance occurrence, this correla- 
tion probably does not merit further consideration. 

The lack of significant correlations for the group as a whole does not, however, mean that 
values have no relation to performance in Sealab. There were several types of men in Sealab. 
Two well-defined subgroups are the Navy and civilian divers. It is reasonable to assume that 
the men in these two subgroups entered Sealab with somewhat different goals. These differ- 
ences in goals may in turn have been reflected in basic values, as measured by the "Study of 
Values." Thus, while one value may have correlated with performance positively for say the 
civilian subgroup, the correlation on the same value may have shown a negative correlation for 
the Navy subgroup. This was in fact the case. Before presenting the results illustrating this 
point, it is necessary to discuss first the criterion factor scores on which the analysis was 
based. 

Criterion Factor Scores 

In attempting to evaluate performance and adjustment in a complex situation such as Sea- 
lab, it is necessary to use multiple criteria. Ten have been used in the present analysis, and 
more are available for future analyses. The use of multiple criteria has both advantages and 
drawbacks. The principal advantage is that multiple criteria provide a more complete picture 
of behavior than would a single criterion. The principal disadvantage is that the picture is 
fractionated and diffuse, since some criteria correlate with some predictors but not with oth- 
ers. Factor analysis provides at least a partial answer to the choice between a simplistic few 
or a confusing multitude of variables. 

Three factor scores were derived from an analysis of the ten criterion variables. One of 
the factor scores is an unrotated or general factor. For the general factor, each of the ten 



194 



FUTURE SELECTION OF AQUANAUTS 



criterion variables is weighted according to its importance in the factor. Importance is deter- 
mined by the amount of variance accounted for by each of the criteria. Thus the better criteria, 
those which account for more of the variance, are weighted more heavily than are the poorer 
criteria. The weighting or loading of each of the ten criterion variables are given in order of 
importance for the general factor in Table 8. 

Table 8 
LOADINGS OF CRITERION VARIABLES ON THE GENERAL FACTOR 



Criterion 


Loading 


Criterion 


Loading 


Number of Sorties 


0.75 


Human Performance Tasks 


0.55 


Leader Rating 


0.68 


Meal Satisfaction 


0.52 


Diving Time 


0.68 


Up During the Night* 


0.47 


Teammate Choice 


0.62 


Quality of Sleep 


0.38 


Outside Telephone Calls* 


0.58 


Change in Diving Time 


0.17 



*Fe'wer considered better. 



Examining the factor loadings in Table 8 and the correlations between criteria and demo- 
graphic characteristics in Table 7, it is heartening to note that the five most important crite- 
ria according to their loadings are also the five criteria which correlated with the demographic 
variables. Thus, those things which are important are predictable. 

The unrotated or general factor, loadings for which are presented in Table 8, weights each 
criterion against every other criterion and thus provides information regarding the relative im- 
portance of each criterion. In the definitions of criteria, however, different types of criteria 
were identified. Whether or not such types of criteria "hang together" mathematically can be 
determined by rotating the factor matrix. Rotating the matrix is a technique which maximizes 
loadings on one group of variables while minimizing loadings on another. 

Two factors emerged from the rotated matrix. The first we will call a work factor, and 
the second an evaluation-adjustment factor. Loadings for the criteria are presented in order 
of importance for these two factors in Table 9. 

Note that the heaviest loadings on these two factors are considerably higher than are the 
heaviest loadings on the general factor. Similarly, the lightest loadings are much lower, many 
of them nonexistent. Note also that those two factors are relatively independent. That is, 
those variables loading heavily on one factor load lightly on the other factor. 

An examination of the loadings justifies the names of these two factors. For the work fac- 
tor, the two strongest work variables, diving time and number of sorties, have near maximum 
loadings. Number of human-performance tasks completed and change in diving time, the other 
two work variables, are among the top five variables. Only two nonwork criteria, outside tele- 
phone calls and leader rating, have even modest loadings. The other factor, evaluation- 
adjustment, shows the opposite pattern. Teammate choice and leader ratings, evaluations by 
others, are the top two variables. The only other loadings of any consequence are on two ad- 
justment criteria, outside telephone calls and meal satisfaction. None of the work criteria 
have appreciable loadings on this factor. 



Correlations Between Factor Scores and Values 



Correlations between the three factor scores and the six AUport- Vernon- Lindzey values 
are presented in Table 10. Correlations for the group as a whole are at the top of the table, 
followed by the civilian and Navy subgroups. 



FUTURE SELECTION OF AQUANAUTS 



195 



Table 9 

LOADINGS OF CRITERION VARIABLES ON WORK AND 

EVALUATION-ADJUSTMENT FACTOR 



Work Factor 


Evaluation-Adjustment Factor 


Variable 


Loading 


Variable 


Loading 


Diving Time 


0.91 


Teammate Choice 


0.81 


Number of Sorties 


0.88 


Leader Rating 


0.76 


Outside Telephone Calls 


0.50 


Meal Satisfaction 


0.52 


Change in Diving Time 


0.39 


Outside Telephone Calls 


0.45 


Human Performance Tasks 


0.38 


Number of Sorties 


0.20 


Leader Rating 


0.38 


Human Performance Tasks 


0.18 


Up During Night 


0.14 


Diving Time 


0.02 


Teammate Choice 


0.07 


Quality of Sleep 


0.00 


Meal Satisfaction 


0.00 


Up During Night 


-0.03 


Quality of Sleep 


-0.05 


Change in Diving Time 


-0.39 



Table 10 

CORRELATIONS BETWEEN FACTOR SCORES AND ALLPORT- 

VERNON-LINDZEY VALUES -ALL AQUANAUTS 



Sealab 
Personnel 


Factors 


Values 


Theoretical 


Economic 


Aesthetic 


Social 


Political 


Religious 


All 


General 


0.03 


-0.06 


-0.01 


0.02 


0.03 


-0.10 




Work 


0.04 


0.21 


-0.14 


-0.06 


0.20 


-0.17 




Evaluation - 
















Adjustment 


-0.11 


-0.09 


0.10 


-0.07 


0.06 


-0.10 


Civilian 


General 


0.09 


0.35 


0.07 


-0.47 


0.03 


-0.02 


N= 10 


















Work 
Evaluation- 


0.04 


0.26 


0.26 


-0.52 


0.25 


-0.15 




Adjustment 


0.15 


0.75t 


-0.7lt 


-0.47 


0.25 


0.09 


Navy 


General 


0.31 


-0.12 


0.06 


0.17 


-0.01 


-0.32 


N= 18 


















Work 
Evaluation- 


-0.03 


0.21 


-0.31 


0.20 


0.19 


-0.16 




Adjustment 


0.45t 


-0.39''= 


0.42- 


-0.04 


-0.03 


-0.38 



*Slightly correlated p < 0. 
iModerately correlated p 



10. 

< 0.05. 



196 FUTURE SELECTION OF AQUANAUTS 

For the group as a whole there are no significant correlations between factor scores and 
basic values. This was the case for individual criteria as well. There are, however, several 
correlations between factor scores and values for the civilian and Navy subgroups, and the 
correlations present an interesting pattern. 

On two of the values, economic and aesthetic, there were significant correlations with the 
same factor score, the evaluation-adjustment factor, for the two groups, Moreover, these cor- 
relations were in the opposite direction for the two subgroups. Scores on the theoretical scale 
were correlated positively on the evaluation-adjustment criteria for the Navy divers. At a 
minimum the pattern of these correlations supports the view that Navy and civilian divers en- 
tered Sealab with different goals. It is possible to speculate further on how these different 
goals might have affected performance and adjustment in Sealab. 

The correlations in Table 10 imply that the closer a man in one subgroup was to the mean 
value of men in the other subgroup, the better his performance or adjustment in Sealab was 
likely to be. For example, the Navy subgroup had a higher mean value on the economic scale 
than did the civilian group, and civilian divers seemed to fare better if they were more similar 
to the Navy divers on economic values. The same is true of aesthetic values, with the signs 
reversed. That is, high aesthetic values predicted favorable adjustment for Navy divers, while 
the opposite was true for civilian divers. 

The correlation between scores on the theoretical value scale and the evaluation-adjustment 
factor for Navy divers is also of interest, even though there were no similar correlations for 
the civilian divers. It is not surprising that scores on this value were extremely high for the 
civilian divers, since they were scientists, and the scale is intended to measure theoretical or 
scientific value orientations. Even though the mean value for the Navy divers as a group was 
significantly lower than that of the civilians on the theoretical scale, this value was still the 
highest of all six values for the Navy divers. In other words, the Navy divers were very high 
on scientific values for a group of nonscientists. Furthermore, those with the highest scien- 
tific value scores rated higher on the evaluation-adjustment factor. 

Information from the debrief interviews illustrates the way in which a high theoretical 
orientation may have operated to produce intragroup harmony. Marine life around Sealab was 
a constant source of amusement and diversion. Many of the men spent hours observing fish 
through the portholes. Some of the scientists were engaged in taking a marine-life census and 
observing fish behavior. In the debrief interviews, one of the marine biologists spoke enthusi- 
astically of the ability of one of the Navy divers to see and identify fish, saying, "I trained him 
on observing fish and he got so he could spot them before I could." This same Navy diver also 
commented spontaneously and favorably on his work as an amateur marine biologist. Thus, 
this shared interest appeared to have provided a bond between these two men which acted favor- 
ably on their performance and adjustment. 

Can these men be characterized in more meaningful terms than correlations and mean 
values? While it is in a sense simplistic and misleading to do so, an attempt to identify the 
value patterns associated with better adjustment for civilian and Navy aquanauts may serve to 
illustrate how the Study of Values can be used. It would appear in general that the Navy divers 
fared better in Sealab if they had high scientific interests enabling them to appreciate and un- 
derstand the goals of their scientific colleagues; if their aesthetic orientation enabled them to 
enjoy fully the wonder and beauty of the unique aesthetic experience provided by Sealab; and if 
economic values did not loom too large in their outlook on life. Conversely, it seems that the 
civilian scientists fared better if they were more down to earth, since better adjustment for 
civilians was correlated with lower aesthetic values and higher economic values. This analysis 
may represent a very complex way of saying that people get along better if they understand the 
other fellow's point of view. However, it is important to know the areas in which shared val- 
ues, as measured by these scales, produce this understanding. The results of this study hope- 
fully represent a step toward such knowledge. 

Factor Scores and Demographic Variables 

In Table 11 correlations between factor scores and demographic variables are presented. 
Table 11 also includes a nondemographic variable, Teammate Choice - Pre, which is the 



FUTURE SELECTION OF AQUANAUTS 



197 



Table 11 

CORRELATIONS BETWEEN FACTOR SCORES AND 

DEMOGRAPHIC VARIABLES-ALL AQUANAUTS 



Sealab 
Personnel 


Factors 


Demographic Variables 


Age 


Diving 
Expe- 
rience 


Educa- 
tion 


Birth 
Order 


Family 
Mobility 


Town 
Size 


Team- 
mate 

Choice- 
Pre 


All 

Civilian 
N= 10 

Navy 
N= 18 


General 

Work 

Evaluation- 
Adjustment 

General 

Work 

Evaluation- 
Adjustment 

General 

Work 

Evaluation- 
Adjustment 


0.26 
0.00 

0.55t 
-0.13 
-0.08 

0.28 
0.37 
0.09 

0.6lt 


0.18 
0.10 

0.23 

-0.02 

0.07 

-0.28 
0.16 
0.14 

0.26 


-0.20 
-0.17 

-0.16 

-0.14 

0.01 

-0.66t 

-0.16 

-0.45 

0.10 


0.47t 
0.5lt 

0.27 
0.46 
0.45 

0.60* 
0.50t 
0.45* 

0.17 


-0.17 
-0.31 

0.22 
-0.51 
-0.52 

0.42 
-0.11 
-0.19 

0.07 


-0.481: 
-0.38t 

-0.27 
-0.42 
-0.05 

-0.46 

-0.53t 

-0.57t 

0.21 


0.44t 
0.07 

0.641: 

0.27 

0.05 

0.83t 
0.44* 
0.10 

0.59t 



*Slightly correlated p < 0.10. 
IModerately correlated p < 0.05. 
+Highly correlated p < 0.01. 



number of times each man was named as a preferred teammate by the other 27 aquanauts be- 
fore entering Sealab. 

A comparison of Tables 10 and 11 indicates that basic values and demographic variables 
predicted different aspects of behavior in Sealab. In general, the Allport- Vernon- Lindzey val- 
ues tended to correlate with the evaluation-adjustment factor, but not with the work and general 
factors. On the other hand, the demographic variables correlate with the general and work 
factors, but not with the evaluation-adjustment factor. Results on Table 11 also reveal that 
there are no reversals of correlations between demographic variables and criterion factors 
for civilian and Navy subgroups. There were reversals in the case of basic values. This 
means that demographic variables tended to predict similarly regardless of subgroup. The 
low occurrence of significant correlations in the civilian subgroup for demographic variables 
is probably due to the small number of cases, since most of the demographic variables which 
are correlated for the whole group and for the Navy subgroup also have sizable, though non- 
significant, correlations for the civilian group. 



Navy and Civilian Difference 



Since the analyses in Tables 10 and 11 are broken down by Navy and civilian subgroups, it 
may be of interest to examine some of the differences between the two groups. On the criterion- 
factor scores, there were no differences; that is, the Navy and civilian groups performed and 
adapted equally well, according to the three criterion-factor scores. There were small differ- 
ences on two of the separate criteria, teammate choice and meal satisfaction. The Navy divers 



198 FUTURE SELECTION OF AQUANAUTS 

reported slightly greater satisfaction with the meals and were chosen more frequently as 
teammates. Choice as teammates is probably due to the fact that Navy divers tended to choose 
their colleagues rather than civilians, although this was by no means unanimous. There were 
numerous choices across groups. Navy divers being chosen somewhat more frequently could 
also have been due to the fact that, as a group, they were older and more experienced as divers. 
In any case, the differences were slight. There were no differences on any of the work criteria, 
and for practical purposes the groups can be considered equal, 

SUMMARY OF SEALAB II STUDIES 

Since the foregoing discussion is somewhat lengthy and involved, it may be best to review 
the results before discussing how the information obtained in this study might be used in a 
selection program for future aquanauts. 

Ten criterion variables measuring performance and adjustment were used. Four of these, 
the work variables, were number of sorties, diving time, number of human performance tasks 
done, and change in diving time from week one to week two. Four of the criteria are called 
measures of adjustment. They are satisfaction with meals, quality of sleep, number of times 
up during the night, and number of outside telephone calls. The first three of these variables 
are based on self-reports, while the last is an objective record. Two other variables were 
ratings by the team leader and choice as a teammate. A factor analysis of the ten variables 
resulted in three criterion factors which were labeled the general factor, the work factor, and 
the adjustment-evaluation factor. All ten criteria contributed in varying amounts to a score on 
the general factor. On the work factor, the four work variables and outside telephone calls 
made large or moderate contributions. For the evaluation-adjustment factor, leader rating, 
teammate choice, meal satisfaction, and outside telephone calls were the significant components. 

The ten criterion variables and the three factor scores were correlated with six demo- 
graphic variables and six values from the AUport-Vernon-Lindzey Study of Values . The demo- 
graphic variables were age, diving experience, education, birth order, family mobility, and 
size of home town. In addition, a pre -experiment measure of teammate choice was correlated 
with the factor scores. 

Results of the correlation matrices indicate that men who performed better in or adapted 
better to the Sealab environment tended to be older and more experienced divers. They were 
more likely to have been later born rather than first, and to^have been raised in a small town 
and moved less often during childhood. Among the Navy divers, a man tended to fare better if 
he had relatively high theoretical interests, relatively lower economic values, and higher aes- 
thetic values as measured by the AUport-Vernon-Lindzey Study of Values . Among the civilian 
divers, better performance and adaptation was associated with relatively higher economic val- 
ues, lower aesthetic falues, and less education. 

A SELECTION PROGRAM FOR AQUANAUTS 

It would be extremely naive to suggest that the results of the research reported here be 
the sole basis of selecting future aquanauts. By using these predictors alone, one could doubt- 
less select an excellent team of aquanauts. However, there are at least three good reasons 
why these predictors should not be used by themselves. First, it might be difficult to find men 
who met all or even most of the qualifications specified. Second, many well-qualified and po- 
tentially successful men would doubtless be eliminated from consideration. And, third, better 
predictors may be available. The value of these predictors is that they are based on experi- 
ence. Because of their basis in real life they are invaluable and unique. The information 
gained from this study could not be duplicated anywhere, and characteristics of men who per- 
formed best in Sealab can contribute greatly to future selection. The question is, how can they 
and should they be used? 

The selection criteria developed here may best be used in a seven-point program of selec- 
tion. (Seven points are used merely to assist in presenting an outline of a selection program. 



FUTURE SELECTION OF AQUANAUTS 199 

Experience may show that either more or fewer steps are necessary.) The steps recommended 
in the order of their application are: 

1. A call for volunteers 

2. An assessment of the training and experience of each volunteer 

3. Standardized ratings of the man by instructors and supervisors 

4. Similar ratings by his peers 

5. Use of the present criteria 

6. A physical examination 

7. Selection during training 

It should be pointed out that all factors in selection outlined above, except the present cri- 
teria, and peer ratings, were probably used, albeit informally, in selecting the team for Sea- 
lab 11. By this it is meant that, since the candidates were selected on the basis of personal 
knowledge of leaders of the program, it is assumed that reputation and past record played the 
major role in selection. For future operations involving potentially large numbers of men, 
personal acquaintance may not suffice. Therefore an attempt to standardize, formalize, and 
evaluate selection procedures should be the aim of a future selection program. Let us examine 
each of the above steps. 

Call for Volunteers 

It may be self-evident that men taking part in a hazardous or specialized program will be 
volunteers. Nevertheless, the fact that they are volunteers can play an important role in se- 
lection. Careful attention should be given to a complete and realistic portrayal of the opportu- 
nities and dangers involved to insure the recruitment of informed and properly motivated 
candidates. 

Assessment Based on Training and Experience 

Presumably men applying as aquanauts will have had some training as divers, although it 
is possible that this may not always be the case. Assuming that the applicant has attended div- 
ing school, the level of his training and his grades should be considered as factors in selection. 
Conduct and proficiency ratings should be considered, particularly when they comment on a 
man's work as a diver. However, the validity of this information should be examined carefully 
for two reasons. First, proficiency ratings may be based largely on work having little to do 
with diving. Second, the most successful aquanauts may not necessarily be men who have the 
best conduct reports. This mildly heretical suggestion is supported by the lack of correlation 
between measures of both juvenile and adult misconduct and performance in Sealab 11. It is 
quite possible that excellent aquanauts may be found among the ranks of those who occasionally 
"kick over the traces." Some men volunteering for a program like Sealab may crave excite- 
ment and adventure and thus may have some minor blemishes on their conduct records. The 
lack of correlation between measures of misconduct and performance in Sealab does not mean 
that men should be selected who have been in trouble occasionally; rather, it means that infor- 
mation concerning misconduct may be of no use as a selection factor. 

Ratings by Instructors and Supervisors 

In addition to assessing a man's past performance, specific ratings of his work as a diver 
by those who have supervised him in this work should be useful in selection. Letters of rec- 
ommendation are notoriously biased toward favorable comments. In its highly successful se- 
lection program, the Peace Corps has developed an apparently useful correction for such biases. 



200 FUTURE SELECTION OF AQUANAUTS 

Letters of recommendation are requested of three persons for all Peace Corps volunteers. 
The recommenders are informed in detail of the type of qualifications necessary and of the 
importance to himself and others of the applicant's possessing these qualifications. In addition, 
the persons making recommendations are informed that no single negative or lukewarm en- 
dorsement will be definitive in assessing an applicant's fitness. This provision lets the rater 
know that he alone cannot disqualify an applicant. Similarly it protects the applicant from the 
biased viewpoint of a single person rating him. Peace Corps selection officials feel that this 
assurance has resulted in unusually candid appraisals of volunteers. Some variant of this 
technique might increase the validity of ratings for man-in-the-sea volunteers. 

Ratings by Peers 

For a diver, confidence in his buddy is of great importance. It would seem that the most 
valid source of information bearing on his qualifications as a diving partner would be a man's 
diving buddies. Care will be required to develop a useful measure of buddies' reactions, but 
the information provided by such a measure is of sufficient potential to warrant an expenditure 
of time and effort in its development. 

Sealab II Criteria 

The above types of information can be combined with the predictive data available from 
research on Sealab 11, and hopefully from similar ventures. All applicants should be asked to 
complete a battery of background information similar to that collected on Sealab II aquanauts. 
This background data can then be compared and combined with the other information available 
on a man. Details of the method of combining this information are beyond the scope of the 
present discussion, but it can be stated with confidence that an overall assessment of candi- 
dates will be possible. Ideally each man would be assigned a score placing him somewhere 
along a continuum of acceptability. According to the number of men needed, a cutting point is 
selected on the continuum, and those with scores above the cutting point are chosen as candi- 
dates. A physical examination can be the final step in this phase of the process. 

Selection During Training 

If the selection criteria are valid and the group of applicants is large enough so that mar- 
ginal candidates do not have to be accepted, it is possible that no further selection will be nec- 
essary. However, no selection system will guarantee that every applicant will be completely 
successful. Thus selection should continue through the training period. For economic reasons, 
and to spare volunteers embarrassment and disappointment, elimination during training should 
be used infrequently. A good pretraining selection program is the best method of insuring low 
rejection rates during training. 

In summary, valuable selection criteria have been developed from this study of the Sealab 
II aquanauts. An attempt has been made to identify other selection criteria which may have 
been used to select the Sealab team from the available manpower pool and to indicate how the 
use of this information can be formalized and standardized so that future selection will not 
have to depend on personal acquaintance. Whatever selection criteria are used should be 
checked against experience by methods similar to those used in the Sealab II study. The goal 
should be to predict future behavior, performance, and adaptation in undersea dwellings, from 
past behavior. 

The process of selection should be conceived of as being open ended. That is, it is a proc- 
ess in which new information, based on research and experience, is combined with previously 
acquired knowledge in a developing program. The program should be open ended for at least 
two reasons. First, the science of selection is so young there is always room for improvement. 
Second, requirements may change in any of a number of ways. If man is to invade and inhabit 
the continental shelf for increasingly diverse reasons and in increasing numbers, different 
skills will be required of team members. As he learns more of the economic, scientific, and 
military potential of undersea habitation, new ways of organizing teams may prove necessary 
or desirable. Continued observation and study of men and teams will help to make operations 
safer and more rewarding personally, and will increase economic efficiency. 



Section III 
MAN-IN-THE-SEA PROGRAMS 



Chapter 28 
PHYSIOLOGICAL STUDIES IN SEALAB II 

G. F. Bond 

U. S. Navy Special Projects Office 

Washington, D. C. 

Although Sealab 11 was not designed to yield a large amount of physiological data, it was 
nevertheless considered prudent to pursue a course of selective monitoring of personnel of each 
of the three teams for overall safety of the operation. Previous meticulous physiological stud- 
ies, conducted through the Genesis series,'' and subsequently in Sealab I, had indicated that the 
great majority of physiological parameters examined would show no significant change under 
conditions of high pressure and exotic gas mixtures. It was therefore considered adequate to 
monitor only those vital functions of our human subjects which might assist topside control in 
medical management of the experiment. 

In consequence, the number of physiological tests performed in Sealab II was severely cur- 
tailed, and the selection of monitored subjects was likewise limited. A program was established 
to provide for intensive physiological sampling from two or three aquanauts of the first two 
teams on a daily, alternate daily, then each-third-day basis. Sampling included extraction of 
about 20 cubic cemtimeters of blood daily for topside analysis, with appropriate quantities of 
urine and saliva for additional inspection. In addition, the majority of aquanaut personnel par- 
ticipated in daily studies of pulmonary function, electrocardiographic recordings, body- 
temperature control, exercise tolerance, and a number of routine physical tests. 

By and large, the results of tests on selected subjects in the three teams of Sealab n were 
essentially negative. All of the classical blood chemistries which were performed fell easily 
within the normal ranges during the experiment. These tests included blood sugars, blood urea 
nitrogen determinations, creatinines, all serum electrolytes, and calcium and phosphorus values 
and ratios. Blood morphological values were likewise followed on a regular basis, with no evi- 
dent deviation from the normal pattern. Urine specimens remained generally within acceptable 
limits, considering the problems of accurate collection and analysis. 

Nevertheless, the following chapters will show, there were suggestive trends in certain 
areas which will warrant further intensive investigation under controlled laboratory conditions, 
and with considerable refinement of techniques. For example, the red-blood-cell count of the 
subject (MSC) who was exposed for 30 days of continuous stay to partial pressures in excess of 
200 mm Hg of oxygen, showed a linear decrease in red-cell count, although no evidence of cell 
destruction could be demonstrated. Likewise, most of the "Stress" enzymes and other indica- 
tors of stress were clearly elevated during the first three to five days of hyperbaric exposure- 
indicative of some initial problems which require further investigation. 

During Sealab II, attention was particularly directed to examination of the "stress enzymes," 
since these indicators, together with the corticosteroid determinations, had demonstrated great- 
est liability during past human exposures. As will be seen in the following chapters, these data 
give provocative evidence of an increased stress effect on the aquanaut subjects during the first 
three-to-five-day period of undersea exposure, with a slow return to normal values. Of the 



*Extreme pressure-chamber studies by Capt George Bond at the Submarine Medical Center 
New London, Connecticut which demonstrated that men could live in an artificial helium- 
oxygen atmosphere at a simulated depth of 200 ft for prolonged periods and not realize any 
harmful effects. 

203 



204 PHYSIOLOGICAL STUDIES 

eight blood stress factors examined, LDH (lactic dehydrogenase) provoked greatest interest, 
since values for this enzyme are generally considered to be proportional to a degree of tissue 
damage. Unfortunately, advanced stratifying techniques could not be utilized with the limited 
facilities of Sealab 11; hence, the particular organ responsible for the observed LDH overpro- 
duction could not be pinpointed. It would appear that stress indicators are probably the most 
sensitive physiological warning signals available to topside monitors, and this fact will be 
suitably exploited in future undersea experiments. 

In summary, it would appear that two important physiological observations are evident. 
First, almost all physiological functions demonstrate a sharp deviation from baseline values 
during the first three to five days of exposure in all Sealab experiments. Secondly, the accep- 
ted indicators of physiological/psychological stress are generally elevated during the first few 
days of exposure. These two provocative observations indicate an urgent need for additional 
research in this area. 



Chapter 29 
THE TELEMETERING OF HUMAN SUBJECTS AND ANIMALS UNDER WATER 

Samuel Bellet, Allan Slater, and David Kilpatrick 

Philadelphia General Hospital 

Philadelphia, Pennsylvania 

INTRODUCTION 

To obtain information relative to the interaction of cardiac response to under water work- 
ing tasks and swimming, acoustic underwater telemetering of EKG* signals from the swimmer 
to the habitat and hard wire transmission to the staging vessel was experimentally performed 
in Sealab II operations. Success was achieved in obtaining a limited number of electrocardio- 
grams. A number of technical difficulties were revealed, as well as possible solutions thereto. 

Ultrasonic telemetry was selected as the method for transmitting information from the 
swimmer to the habitat. After studying a number of techniques of modulating an ultrasonic 
carrier, frequency modulation was chosen as the best method to transmit the data in the trans- 
mission medium (sea water). The factors considered were bandwidth, medium inhomogeneity 
effects, multipath propagation, and battery energy utilization. 

The design of a sonic telemetry system is a relatively simple problem. The signal band- 
width of a few hundred cycles per second for cardiac electrical activity, for example, is so 
small that frequency modulation is compatible with the medium. The primary limitation of 
water as a communication medium is carrier bandwidth. This is due to the rapid increase of 
propagation attenuation with increasing frequency. A typical submarine voice communication 
system must heterodyne the voice signal to a higher but still audio frequency, and "transmit" 
single sideband in order to limit the carrier bandwidth to the same value as the signal, or 
about 3,000 cps. It is practical to utilize frequency modulation with a total deviation of less 
than 3,000 cps for a cardiac signal of 100 cps bandwidth. Frequency modulation has many ad- 
vantages for the accurate transmission of information in a noisy medium. 

BASIC SYSTEM 

The complete data link can be broken down into four subsystems (Fig. 79). Electrodes 
pick up electrical signals induced by the heart in the chest wall. These signals are relayed to 
the transmitter, where they are converted to a frequency- modulated acoustical wave. This 
wave is propagated from the diver through the sea to the receiver and is processed to recover 
electrocardiographic information. Output from the receiver is recorded with a Sanborn re- 
corder located in the Berkone staging vessel. 

Electrode Details 

Two types of electrodes have been used. All tests prior to delivery of the equipment to 
Sealab II used Beckman electrodes, while tests at Sealab n used both silver-silver chloride 
(Beckman) and tin (Sem-Jacobsen) electrodes. Electrode construction is shown in Fig. 80. 



* Electrocardiogram. 

205 



206 



TELEMETERING UNDERWATER 





-ON DIVER 


) 


ELECTRODES 

ATTACHED TO 

DIVER 




TRANSMITTER 
(MOUNTED ON 
SCUBA TANK) 





i 






RECEIVER 




DATA 
PRESENTATION 





Fig. 79. Basic telemetry systems 



-SEA LAB ) 



( BERKONE AND ) 

PGH 





Fig. 80. Basic electrode construction; A - silver- 
silver chloride (Beckman) electrode, B - tin (Sem- 
Jacobsen) electrode 



Both types of electrodes were attached to the chest with waterproof tape; the silver-silver 
chloride also employed double-backed tape washers and "Stomaseal Disks" to achieve water 
tightness. The tin leads (developed by Dr. Sem-Jacobsen) were simply taped to the chest or 
were glued on prior to going down into the Sealab habitat. Electrodes were placed as shown 
in Fig. 81. 



Transmitter Details (Electrical) 

The basic block diagram of the transmitter is shown 
in Fig. 82. Electrocardiographic signals from the elec- 
trodes drive the input preamplifier, which provides 
differential amplification of the signals from the two 
chest leads. Variations in signal levels induced by 
changing impedance of the skin at the electrode contacts 
is minimized by the 3.3-megohm input impedance. In 
addition, the preamplifier has a high value of common 
mode rejection and a large common mode voltage- 
handling capability to minimize requirements for good 
contact of the ground electrode. 

Output from the preamplifier is capacitively coupled 
to a single- ended amplifier with a gain of 50. The am- 
plifier output, in turn, is capacitively coupled to the 
base junctions of a multivibrator. Variations of the 
base voltages shift the frequency of oscillation of the 
multivibrator from its natural frequency of 25.0 kc/sec. 
Frequency shifts of approximately 250 cps per millivolt 
of EKG voltage at the electrodes are obtained. Output 
from the multivibrator drives apush-pull amplifier which 
drives the transducer. The resultant ultrasonic energy containing electrocardiographic infor- 
mation propagates through the water to the receiver. 




Fig. 81. Placement of elec- 
trodes on subject 



TELEMETERING UNDERWATER 



207 




ANALOG TO 
FM CONVERTER 



POWER 
AMPLIFIER 



TRANSDUCER 



Fig. 82. Block diagram, basic transmitter 



Transmitter Details (Mechanical) 

The transmitter is housed in a 2 -in. -diameter pipe with an overall length of 14 in. A sin- 
gle five-pin connector serves as the input for the three electrocardiographic leads and as the 
power switch. The transmitter turns on automatically whenever the electrocardiographic leads 
are plugged into the connector. About four hours of operation can be obtained from each bat- 
tery set. Batteries can be reached by removing the instrument casing. 

Receiver 

A block diagram of the telemetry receiver is shown in Fig. 83. Acoustical energy from 
the water is converted into electrical energy by the receiving transducer. Signals from the 
transducer are amplified by a three-stage tuned amplifier with a center frequency of 25 kc/sec. 
Output from the tuned amplifier drives a variable-gain stage. Normally, the gain is set to 
maximum. However, when the diver is very close to the receiver, clearer signals can be ob- 
tained by reducing the gain setting. The sinusoidal signal from the variable-gain amplifier is 
converted to square-wave form by a Schmitt trigger, whose triggering level is set to zero volts. 
Output from the Schmitt trigger synchronizes a multivibrator to exactly half the frequency of 
the received signal. In the absence of a signal, the multivibrator oscillates at a natural fre- 
quency of 12.5 kc/sec. Therefore, there is always a signal coming from the multivibrator, 
which prevents excessive excursions of the output of the FM detector in the absence of received 
signal. FM detection is achieved with a monostable multivibrator followed by a low-pass filter. 
The monostable multivibrator generates a 40-microsecond pulse each time the multivibrator 
output swings positive. The average output level from the monostable multivibrator increases 
with received signal frequency. This average value is extracted by the low-pass filter (80 cps 
cutoff frequency) and is taken as the electrocardiographic output after passing through an emit- 
ter follower and gain control. 



SEALAB INTERFACE 

The system layout for the equipment as installed at Sealab II is shown in Fig. 84. 

The hydrophone and receiver were placed within the Sealab habitat. As the diver swims 
in the water, the received electrocardiographic signals are relayed topside for immediate ob- 
servation. Cables between Sealab and the Berkone were shared with a wedge spirometer. The 
signals were recorded in the medical van on a Sanborn recorder. Preparations for relay to 
Philadelphia via Bell Dataphone were also made. 



208 



TELEMETERING UNDERWATER 

ADJUSTMENT #1 













3 STAGE 




GAIN 








AMPLIFIER 




CONTROL 
















1 




RECEIVED 
SIGNAL 
STRENGTH 
METER 








ADJUSTMENT #5 






1 










SCHMITT 
TRIGGER 








r 




ADJUSTMENT 




# 2 


ADJUSTMENT # 3 







MULTIVIBRATOR 



ONE 
SHOT 



EMITTER 
FOLLOWER 



CENTER 

FREQUENCY 

METER 



LEVEL 



ADJUSTMENT #4 



I EC6 

OUTPUT 



ADJUSTMENT CHART 



ADJ 
NO 


ADJUSTMENT PROCEDURE 


LOCATION 


1 


ADJUST FOR CLEAR ECG 


FRONT 
PANEL 


2 


ADJUST FOR TRIGGERING AT ZERO CROSSINGS 
OF MULTIVIBRATOR OUTPUT 


REAR 
PANEL 


3 


ADJUST FOR ZERO ON FREQUENCY METER 
WHEN INPUT SIGNAL IS 25 KILOCYCLES 


REAR 
PANEL 


4 


ADJUST FOR SUFFICIENT OUTPUT TO DRIVE 
DISPLAY DEVICE 


REAR 
PANEL 


5 


ADJUST FOR PROPER INDICATION OF SIGNAL 
LEVEL 


REAR 
PANEL 



Fig. 83. Block diagram, receiver 







STAGING 


VESSEL 










PHILADELPHIA 


GENERAL HOSPITAL 






SANBORN 
RECORDER 












r* 


SANBORN 
RECORDER 












TELEPHONE 
COMPANY 












PATCH 
PANEL 














DATAPHONE 






























L 


DATAPHONE 
















L 


TAPE 
RECORDER 
































SEA 


LAB 


HABITAT 










DIVE 


R 






PATCH 
PANEL 




HYDROPHONE 

a 

RECEIVER 






TRANSMITTER 




ELECTRODES 







































Fig. 84. Block diagram, complete telemetering system 



TELEMETERING UNDERWATER 



209 



RESULTS 

The following tests were performed at the therapeutic pool at the Philadelphia General 
Hospital vl3 ft wide and approximately 25 ft long) and at the local YMCA (pool is approximately 
40 X 70 ft) to confirm basic operations capability of the system (Fig. 85). Tests indicated that 
all circuits were performing within specifications. 




A second series of tests were performed 
in the Little Magathey River (Maryland) to test 
the operation of the system in a large salt- 
water body. Good signals were obtained at 
distances up to 50 ft. Beyond that, range drop- 
out was severe. Reasonable interpretation of 
range from this data is not possible due to the 
fact that the water conditions were not as ex- 
pected; i.e., actual depth of the water was 3.0 
ft, with much swamp grass which absorbed the 
signal. Figure 86 shows data obtained at a 
distance of 30 ft. The data at this time showed 
significant amounts of muscle tremor due to 
the fact that excessive exertion was needed to 
move through the vegetation. When the subject 
relaxed, significant improvement in the quality 
of the received signal was observed. 

Data are also shown (Fig. 86) when the 
diver was at a distance of 60 ft from the record- 
ing appartus. Although the data showed signifi- 
cant amounts of dropout, heart- rate data were 
still available. 



1 1 1 1 


1 1 


1 



Fig. 85. Experimental tests of sonic 

telemetry equipment 

A and B - in 15 « 25 ft pool 

C and D - in 40 ^ 70 ft pool 



Final study of the equipment before deliv- 
ery to Sealab was performed at the Aquarama 
in Philadelphia at a depth of 10 ft and a distance 
of 50 ft from the recording apparatus. Before 
entry to the water, a baseline air test was per- 
formed using the equipment. The results are 
shown in Fig. 87. Figure 87 shows data ob- 
tained at a distance of 20 ft after the diver had 
undertaken extreme physical exertion. 



Tests with the first diving team have 
yielded high-quality electrocardiograms at 
distances up to 100 ft and at a depth of 220 ft 
(Fig. 88). Additional tests performed under 
similar conditions yielded similar results. No tests were performed beyond this distance; con- 
sequently, the exact determination of maximum range is hot possible. 



FUTURE RECOMMENDATIONS 

Experience at Sealab has shown that the underwater physiological telemetering equipment 
requires too much time and experience from personnel in Sealab and topside. To alleviate this 
problem, a new design policy emphasizing ease of installation and operation of the equipment 
will be adhered to. The following factors will be studied to simplify equipment operation. 



1. Electrode Placement 



In order to obtain good electrocardiograms, the use and placement of proper electrodes is 
crucial. Personnel in the Sealab found that the Beckman electrodes required too much time to 



210 



TELEMETERING UNDERWATER 



jVl/^t/Wlr'^ 



^t\ 



AilMyM A^Im[a^[a^ 



MUSCLE TREMOR - 



J I L 



-h 



SUBJECT RELAXED- 



J I L I I I I I I I I 



J I I I I 



J I I L 



nf^^'ijlSln^i^i'l^r'i^^ W^^^^ iS^p U\^^^^^^^^,^'M-, vl 



J I L 



J 1 I \ I L 



Fig. 86. Experimental test of sonic telemetry equipment in Little 
Magathy River, A - s"wimmer approximately 30 ft awray, B - swim- 
mer approximately 60 ft away 



y~-1 



[^ 



J I I I I I I I I I I I I I I I L 



MpY^ 



^\4\4p 



H 



AaJa^[^J/n^H[m 



/ihHri 




A 



J I I I I I I 



I I I I I I 



Fig. 87. Experimental test of sonic telemetry equipment at Philadel- 
phia Aquarama, A - in air, B - in water at a range of 20 ft, after ex- 
treme physical exertion 



put on; in addition, the procedure was too complicated. Consequently, the electrodes were often 
put on improperly, and signals with considerable extraneous noise were therefore obtained. 
Studies are being conducted to obtain a special electrode design optimized for use under a wet 
suit. For example, a thinner electrode that can be held in place by the pressure of the wet suit 
will be considered. 

Recent studies at the Philadelphia General Hospital indicate that it will be possible to elim- 
inate the third or ground lead entirely. If further analysis of the two- lead system proves suc- 
cessful, the time required to put leads on will be reduced by one-third by thisfactoralone. The 
goal will be to design effective electrodes that can be put on easily in a few minutes. 



2. Simpler and Quicker Mounting to the Scuba-Tanks 

In the equipment delivered to Sealab 11, the transmitter was attached to the scuba tanks by 
two steel bands which were tightened in place by use of a screwdriver (Figures 89 and 90). It 
is an easy matter to redesign the mounting in the form of a snap- on type device that will allow 
attachment and removal of the transmitter in a few seconds without tools. 



TELEMETERING UNDERWATER 



211 




I I I I I 1 I I ' I I I I I I I I I I I I 1 I I I I I I I I 



I I I I I I I I I I L 



Fig. 88. Experimental test of sonic telemetry equipment during Sealab 
II; all runs at Z20 ft depth and approximately 100 ft from the Sealab 11 
habitat 



3. Placing of the Receiver on the Staging Vessel 

In Sealab II the receiver and hydrophone were placed in the Sealab habitat. The signals 
from the receiver were sent topside by a cable system which caused considerable difficulties. 
Approximately 50 percent of the tests attempted were aborted because of improper connections 
at the patch panels, intermittent failures in the connectors to these panels, and loss or mis- 
placement of the cables between the receiver and the patch panels. 

In future operations, these problems should be bypassed by placing the receiver on board 
the staging vessel. This procedure will eliminate the need for the entire patch- panel cable 
system (except as a backup) and will also save space in the Sealab habitat. This procedure 
will also eliminate the work required by the aquanauts of turning the receiver on and checking 
its operation, etc. (A second hydrophone placed onboard Sealab and connected to the staging 
vessel by the patch panel will allow reception of signals for testing the gear prior to entry into 
the water.) This hydrophone will also serve as a backup in case difficulty is experienced with 
the other hydrophone. 

4. Automatic Receiver and Recorder Operation 

It is a simple matter to design a squelch circuit into the receiver that will automatically 
activate the recorder whenever signals are being received from the transmitter. In this mode 
of operation, the receiver can be left on all the time. When it is necessary to record data, the 
diver will merely have to enter the water. As soon as the receiver detects the incoming signal 
it will automatically activate the system and record the information, and it will also automati- 
cally turn off when the diver leaves the water. Provision for bypassing this mode of operation 
will be provided in the event that it does not function properly. 



5. Future Telemetry Systems 

The following parameters are candidates for the additional channels. 



212 



TELEMETERING UNDERWATER 



Body Temperature — Body- temperature 
data are of prime importance, since one of the 
limiting factors to man's performance in the sea 
is his ability to endure loss of body heat to the 
water. Telemetering of body-temperature 
data should greatly help in the evaluation of 
the various experimental heated wet suits. 



Fig. 89. Sonic transmitter with case 
removed 



Additional EKG Leads — It is well known 
in medical practice that more than one elec- 
trocardiogram is necessary to get a maximum 
amount of data from the heart. Additional 
leads will provide the necessary data. 

Electroencephalograms— Telemetering of 
the EKG may be implemented in the telemeter- 
ing system, since the bandwidth requirements 
for the EKG are actually less than the elec- 
trocardiogram. It would merely be necessary 
to provide a higher gain amplifier in the trans- 
mitter to compensate for the smaller signal 
levels of the EKG. 

A Voice Channel — Addition of a voice chan- 
nel will be very helpful in correlating the data 
received for the type of physical activity. In 
addition, the voice channel would also serve 
as an excellent means of communication be- 
tween divers and personnel on Sealab. The 
bandwidth requirements for a voice channel 
are considerably greater than those of the 
EKG channel; consequently, the design of the 
voice channel might not be practical in view 
of our transmitter configuration. However, 
the great usefulness of the voice channel will 
make it worthwhile to investigate. 



6. Extension of Transmitting Range and Improvement of Signal 

In tests at Sealab to date, high-quality signals have been received at the maximum distance 
tested (100 ft through the water). Therefore, the range of the system in its present form is 
greater than 100 ft. However, significant improvements can be made in the efficiency of the 
final amplifier of the transmitter. In addition, low- noise transistors can be used in the front 
end of the receiver and the EKG preamplifier of the transmitter. Both of these changes should 
result in significant increases in range and reductions in the amount of noise in the received 
electrocardiogram . 



7. Packaging 

The design philosophy for packaging future equipment should be to allow for maximum 
flexibility of the equipment. For instance, all telemetry channels will be constructed as plug- 
ins to the basic transmitter. Several plug- ins will be constructed. The plug- in will be chosen 
to telemeter the data for a given mission. As an example of plug- in types, there will be a 
single- lead EKG plug- in which will give the same performance as the equipment used on Sealab 
II. The second type of plug-in will consist of four temperature channels. Another example 
would be a plug- in designed for one EKG and one EEG channel. The advantage of the plug- in 
system is that if one particular data type is unsuccessful, other plug- ins can be used so that the 
system will not be rendered useless. 



TELEMETERING UNDERWATER 



213 




Fig. 90. Sonic transmitter in place on a swimmers scuba tanks 



8. Backup Equipment 



Accidental breakage of the telemetry transmitter and occasional loss of cables reduced the 
number of tests performed. In the future, several extra pairs of EKG leads, cables, and other 
support equipment should be provided. 



Chapter 30 
ADAPTATION TO ENVIRONMENTAL STRESS IN SEALAB II 



Steven M. Horvath and Fred W. Kasch 

Instiute of Environmental Stress 

University of California 

Santa Barbara, California 



Responses of man to various natural environmental stresses can be evaluated by prelim- 
inary studies in simulated environments. Although the environment of Sealab II may not be con- 
sidered as naturally occurring yet it is obvious that it soon may well be one in which men will 
have to live for extended periods. The combined stresses of cold water, high temperature and 
humidity, and work present a complex of environmental stresses that may best be studied at the 
site, but considerable insight into the effects of such a stressful situation can be obtained by 
appropriate studies conducted prior to and immediately after the exposure. The data being pre- 
sented represent such an evaluation based on two tests of working capacity and one of cold ex- 
posure. The subjects were nine divers from Sealab 11, first studied before and again after their 
15 days in Sealab II. These men also had an additional stress of 36 hours of decompression. 

Table 12 
PHYSICAL CHARACTERISTICS OF SEALAB H SUBJECTS 



Subject 


Age 

(yr) 


Height 
(cm) 


Weight (kg) 


Surface Area 
(M^) (PRE) 


Predicted Basal 

Metabolism 

(ml/min) 


Pre 


Post 


MM 

JL 

RB 

FJ 

JR 

WM 

RS 

WC 

GI 


38 
35 
35 
39 
36 
32 
28 
36 
37 


171 
165 
178 
170 
181 
189 
194 
183 
176 


72.6 
70.3 
81.6 
66.0 
81.6 
91.1 
109.8 
96.9 
97.1 


71.6 
70.4 
80.8 
68.5 
78.8 
85.7 
106.3 
92.7 
99.9 


1.85 
1.76 
1.97 
1.76 
2.03 
2.19 
2.40 
2.19 
2.13 


244 
232 
265 
232 
268 
293 
327 
289 
280 


Mean 


35 


179 


85.2 


83.8 


2.03 


270 



These data are preliminary in nature, but they do suggest certain alterations in capacity to 
perform and indicate the need for additional studies of men exposed to environments such as 
present in Sealab n. Table 12 presents certain of the physical characteristics of the nine men 
studied. The first test was a modified maximal work-capacity test whose primary purpose was 
to determine the maximal oxygen uptake of these divers. The data presented in Table 13 in- 
dicated that these men have a level of maximum work capacity which was within the average 
range (for their age) of the values obtained by Astrand and Robinson. Two of the men were 
slightly (10 to 20 percent) below the average. No appreciable shift in maximum oxygen uptake 
was noted as a consequence of their exposure to Sealab H, although the absolute time the men 
could work was decreased in six subjects. A decrease in one subject was due to stoppage of 
his own volition, and a second subject was stopped because of some questions regarding his 
electrocardiogram. There are other evidences that these men during their post-test time had 
some decrease in their effective responses to a maximum work load (Table 14). The oxygen 
debt was greater and the level of blood lactates higher in the second test. Subjective evaluation 

214 



ADAPTATION TO ENVIRONMENTAL STRESS 



215 



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t- 


CD 


CO 


CM 


in 


CO 


Oi 


OO 


CO 


^ 


rf 


CO 


t- 


t- 


jg Q J 


(M 


OJ 


to 


*~*. 


o 


O 


1-1 


<* 


o 


CO 


T 


00 


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CO 


O 


CO 


■*. 


■^ 


■^ 


d 


d 


CO 


r-i 


d 


l> 


1-H 


d 


CM 


d 


d 


in 


CO 


^ 


d 


CM 


co' 


tH 


.-1 


T-H 


T-* 


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"-* 


tH 


'-' 












1-< 


1-H 


f-i 






cd -— 


c 






































• c 


































* 






as "^ 


o 


O 


o 


■<*' 


CO 


in 


o 


o 


o 


o 


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CO 


CO 


CO 


CD 


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CO 


CO 


?.^ 


= 


CO 


CM 


o 


CO 


1-H 


CO 


CO 


in 


CO 


CO 


CO 

1-1 




CM 


o 


CM 


CD 


1-1 


CM 


s^^ 


a, m 








































c 






































£ 


o 


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00 


tT 


o 


T-* 


o 


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CO 


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* 
CM 


CO 


in 


-rr 


CM 




CO 


CO 


CO 


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tr- 


CO 


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CO 




CO 


CO 


■'T 


O 


CD 


CO 


te 


in 


1—1 


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1-H 


t-H 


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1-1 


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T-I 


^ 


T-l 




C 






































< 


a 


CO 


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in 


) 


CD 


o 


in 


-cf 


c- 


i> 


05 


1 


1 


^ 


CO 


•^ 


CO 


tr-; 


&.S 


o 

CO 


CD 


CD 


in" 




CO 


in 


in 


in 


CO 


CD 


in 


1 


1 


in 


d 


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o ^ 


<a> 














































































S 












































































X 


S 




CD 










tj' 






i-t 


CD 


CO 


CO 


CO 


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00 


CD 


O 


o 


^ 


1 


in 


1 


1 


I 


1 


d 


1 


1 


CD 


d 


CD 


CO 


CD 


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d 


CO 


CO 


> 


<a) 




CO 










CO 






CO 


CO 


CO 


CM 


CM 


CM 


CM 


CO 


CO 




. 'c 


o 


CO 


CD 


CD 


in 


o 


CD 


in 


^ 


a> 




CD 


CM 


CO 


CD 


CO 


[> 


CD 


S £ 


o 


■-; 


t- 


t> 


CO 


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■^ 


■^ 


o 


CD 


-*' 


CM 


CD 


■*. 


C- 


in 




CD 


(U 


> J 


c- 


CM 


CD 


in 


CO 


d 


d 


r-i 


CO 


d 


1-4 


d 


V 


■* 


d 


CO 


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CD 


cn 


CO 


■^ 


TJH 


"^ 


CO 


TT 


■* 


CO 


CO 


CO 


in 


TT 


in 


-* 


t- 


CO 


•*** 


CO 






































1 








































r-t 


O 


CO 


CO 


CO 


M* 


■•-t 


CT> 


CO 


03 


o 


-<r 


CM 


CO 


CD 


-^ 


Oi 


O 




c 






































^ 








































0) 

o 


s 






































,^li 


CO 


O 
CM 


in 

CD 


in 

CM 


CO 


CO 
CO 


oo 


O 


t> 


00 


CO 
CD 


in 
d 


CO 

d 


CO 


CM 

in 


t- 


00 
1-H 


cm' 




CM 


CM 


CO 


CO 


CM 


CO 


CM 


co 


CM 




CM 


CM 


OO 


CO 


CO 


co 


CM 


CM 




CSI 


in 


CO 


c- 


in 


^ 


C- 


in 


CD 






















•-I 


Oi 


CO 


o 


o 


o 


Oi 


O 


1 


1 


1 


i 


1 


1 


1 


1 


1 


■^ 


^ 


d 


d 


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^ 


d 


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— . C 






































ii 






































in 


o 


Ol 


CM 


o 


in 


TT 


CO 


CD 


o 


CM 


CM 


o 


o 


^ 


CO 


in 


in 


S on 


o 




CO 


CO 


o 


Oi 


O 




CO 


o 


o 


Oi 


OS 


cr> 


o 


00 


o 


c- 


(M 


CM 


•-< 


T-* 


CM 


1-" 


CM 


(N 




CM 


CM 


1-H 


1-H 




CO 




CO 








































^^ 






































. c 


^ 


CO 


,— ( 


in 


TJ- 


CO 


^ 


O 


in 


CO 


in 


CD 


o 


CO 


,_( 


1-H 


o 


c- 


Max 

Vent 

(L/mi 


CO 


CD 


o 


CO 


[r- 


■-; 


CO 


•-| 


in 


1-* 


CO 


C- 




00 


CM 


CO 


CO 


CM 


cji 


tr-' 


in 


d 


[> 


CO 


in 


CO 


CO 


in 


^ 


d 


^ 


^ 


co' 


^ 


c- 


d 


OS 


CO 


CO 


CD 


E^- 


CO 


CM 


o> 


oo 


Oi 


oo 


o 


oo 


CO 


Ol 


o 


00 


o 














^ 










^ 












.-H 




c 








































1^ 


•^ 


CO 


<r-l 


Oi 


O 


o 


■^. 


■^ 


o 


■^_ 


o 


CD 


CO 


CO 


CO 


in 


■^ 


CO 


,o 


in 


■^ 


CO 


CO 


CO 


■<*« 


CD 


d 


CM 


I> 


in 


d 


"'"3^' 


tT 


CM 


d 


d 


CO 


> 


,^ 


■^ 


TT 


■^ 


^ 


tT 


■^ 


■«J' 


-* 


CO 


■* 


■* 


■* 


^ 


^ 


'iJ" 


CO 


CO 


CO 




S 






































c: 


CO 


CO 


CD 


CO 


CO 


00 


-^ 


tT 


CO 


CO 


^ 


o 


o 


CD 


O 


* 

CD 


■1— 

CO 


c- 


1 


o 


CM 


CM 


CO 


CD 


05 




o 


in 


■^ 


in 


<T> 


o 


l> 


CD 


"^ 


CO 


CM 


s 


CO 




^ 


Oi 


in 


Oi 


•-| 


CO 


o 


in 




t> 


o 


in 


CD 




in 


CO 


CO 


CO 


CO 


CM 


CO 


CO 


in 


CO 


CO 


CO 


CO 


CO 


CO 


CO 


CO 


■<r 


CO 


CO 


- = 






































Ex. Tes 

Duratio 

(mln) 


























in 












^ 


^ 


CJi 


CT> 


CM 


o 


CO 


Oi 


in 


o 


O 


^ 


d 


in 
d 


CO 


O 


CO 


in 
d 


(M 


CM 


•— t 


»— < 


CM 


CM 


CM 


I— I 


1—1 


CO 


CO 


CM 








CM 










































, . 






































- -U 






































rt a.o 






































o £" 


1 


in 


in 


•-' 


CD 


i-H 


t- 


o 


CO 


en 


t> 


1 


1 


o 


CD 


•* 


1 


CO 


fll Ql CIJ 




d 


d 


d 


1-4 


CO 


CM 


•^ 


d 


1-1 


d 


1 


1 


CM 


d 


^ 


1 


^ 






































tr; 






































(0 






































O 


CM 


CO 


in 


CD 


in 


O 


CO 


o 


in 


o 


C- 




cr> 


in 


O 


1-H 


o 




CO 


TT 


Cl 




CD 


00 


t- 


Ol 


in 


CM 


in 


CD 




CD 




CM 


CO 


CD 


T 


CO 


CM 


CO 


in 


CM 


Oi 


T 


CO 


CM 


o 


CM 


1 


CO 


CO 


in 


CO 


CO 


O 


d 


d 


d 


d 


d 


d 


d 


d 


d 


d 


d 




d 


d 


d 


d 


d 




^ 
















1o 


















o 


to 
















0) 


















(1) 

3 
C/3 






E 




^ 


CO 




^ Z "^ 


•-3 


cd 


"-3 


'-3 




CO 




O 



o a) ^ 



216 



ADAPTATION TO ENVIRONMENTAL STRESS 



Table 14 

BLOOD COMPONENTS BEFORE AND AFTER* EXERCISE TEST FOR MAXIMUM 

OXYGEN UPTAKE MEAN VALUES FROM 9 SUBJECTS t 



Blood 


Test I 


Test n 


Difference 














Fraction 


Control 


Post 


Difference 


Control 


Post 


Difference 


Control 

I &n 






Exercise 






Exercise 




Hemoglobin 
















(gm percent) 


16.0 


16.5 


0.5 


16.6 


17.4 


0.8 


0.6 


Hematocrit 
















(percent) 


47.8 


49.7 


1.9 


50.4 


52.6 


2.2 


2.6 


Plasma Protein 
















(gm percent) 


7.57 


8.26 


0.7 


7.64 


8.00 


0.4 


0.07 


Blood Glucose 
















(mg percent) 


103 


137 


34 


112 


127 


15 


9.0 


Blood Lactate 
















(mg percent) 


17.3 


71.2 


53.9 


16.5 


98. 2t 


81.7 


-0.8 


Blood Pyruvate 
















(mg percent) 


0.9 


2.6 


1.7 


0.9 


2.3 


1.4 


0.0 


Plasma Sodium 
















(mEg/L) 


131.6 


135.8 


4.2 


135.3 


137.8 


2.5 


3.7 


Plasma Potassium 
















(mEg/L) 


3.9 


3.9 


0.0 


4.1 


4.0 


-0.1 


0.2 


Plasma Chloride 
















(mEg/L) 


103.5 


104.8 


1.3 


105.6 


106.9 


1.3 


2.1 


Serum SGOT 
















(units) 


9 


10 


1 


10 


11 


1 


1 



*A11 bloods obtained four minutes following cessation of test. 

tThe first test was made prior to entering Sealab II, while the second test was performed two 

days after 15 days in Sealab and 36 hours of decompression. 
tEight subjects - one eliminated due to failure to complete test. 



of the subjects by observers indicated that these test subjects had greater evidence of fatigue 
than was noted on their first test. Again it should be noted that full evaluation of this data has 
not been made and that these statements are preliminary. 

The study made on steady- state work (Table 15) also reflects the general statements made 
above. This impression is verified by the greater number of men (4) who could not complete 
the test the second time. Again, final decision will be made after analysis of the data is 
completed. 

The cold-exposure test consisted of a two-hour exposure to an ambient temperature of 7°C. 
The subjects wore shorts and were lying on a nylon mesh cot during the test. Temperature and 
metabolism measurements offered opportunity for a rather complex analysis of thermal stress. 
Figures 91, 92 and 93 present a preliminary analysis of this data. The data found in Fig. 93 
suggested an alteration in their responses to cold stress. The men were able to increase their 
metabolic levels, with a consequent diminution in loss of body-heat content. The reasons for 
this alteration can not be determined until the data analysis is completed. One problem, not 
clearly identifiable, was the major loss (mean 2 kg) of body weight by the subjects between 
their two visits to this laboratory. 

In brief, there was a suggestion based on the data obtained that some alteration in physio- 
logical function occurred in men living under the conditions present in Sealab 11. Definitive 
statements on these patterns will not be available xmtil these and other data have been subjected 
to final analysis. 



ADAPTATION TO ENVIRONMENTAL STRESS 



217 











































F 








































■'*-' 




OS 


to 


■*. 


c- 


CO 


Cv) 


T 




CD 


eg 


"<r 


OS 


o 


o 


O 


CD 


CO 


■*. 


(U 


sa 


d 


d 


^ 


w 


d 


03 


1 


^ 


w 


d 


d 


CM 


eg 


1-1 


OS 


d 


d 


o 


o 


o 


o 


o 


o 


O 




O 


o 


OS 


o 


o 


o 


o 


OS 


o 


o 


1-t 


'"' 


»H 


'"' 


*-< 


y-i 


»-l 














i-t 






*-i 


tH 


QJ 


Oi 


oo 


in 


CCJ 


C3S 


T 


-^ 


in 


TT 


t- 


o 


CM 


eg 


■^ 


^ 


CO 


eg 


CD 


3 


Li 


o 


CO 


d 


d 


co' 


d 


CO 


d 


d 


d 


d 


d 


d 


d 


d 


t-' 


d 


OS 


a< 


o 


OS 


OS 


o 


OS 


OS 


OS 


OS 


crs 


OS 


<j) 


OS 


o 


crs 


OS 


o> 


Oi 


C3S 


u 








































(U 








































K 








































» 






































Test 

Wt. Los 

(kg) 


OJ 


o 


O 


o 


in 


o 


o 


o 


O 


oo 






in 


in 


CD 


■^ 


,_, 


CO 


CD 


lO 


in 


Ol 


t- 


t- 


oo 


c- 


in 


CM 






i> 


in 


C3S 


CO 


CD 




CM 


T 


in 


CO 


in 


co 


'^ 


CD 


^ 


tn 


1 


1 


CO 


CD 


"^ 


CO 


CO 


oo 


o 


d 


d 


d 


d 


d 


^ 


d 


d 


d 






d 


d 


d 


d 


d 


d 




c 








































o 

" S 












in 




























Ift 


1 


,-, 


tn 


in 


i>^ 


o 


o 


CO 


in 


1 


1 


in 


m 


in 


in 


in 


in 


s 


0) .- 


CM 




CM 


CM 


CM 


OJ 


CO 


CM 


eg 


eg 


I 


1 


CM 


CM 


CM 


eg 


CM 


CM 


o 






































O 
O 


o 














































































IS 


c- 




in 


OS 


in 


o 


o 


CD 


•^ 


CO 






CO 


o 


tn 


oo 


■^ 


OS 


o 


CO 


1 


CD 


in 


CO 


c- 


in 


00 


-<*' 


c- 


1 


1 


■<J< 


CD 


CTS 


CO 


CD 


^r 


^ 




*"" 


'"' 


T-l 


*"* 


*"" 


t-H 


rH 


»-l 












tH 






• "c 






































o 


ll 


o 




o 


■*. 


c- 


N 


o 


CM 


CSI 


crs 






CM 


CM 


CD 


(> 


in 




ai 


1 


d 


d 


CM 


CM 


d 


d 


d 


CO 


1 


1 


in 


d 


d 


t> 


d 


1 


^d 


■^ 




■^ 


■<** 


in 


in 


CO 


CO 


in 


-^r 






CO 


TT 


c- 


TJ* 


-d* 




? 






































rt 









































0) 


• s 


a> 




"5 


CO 


,_, 


eg 


o 




oo 


,_, 






eg 


** 


co 


t- 


OS 




S-S 


Ol 




CD 


c- 


CO 


o 


in 




CM 


tr- 






c- 


O 




in 


o 






t- 


1 


OS 


co 


CO 


o 


oo 


1 


CO 


c^ 


1 


1 


CO 




■*. 


eg 


r-t 


1 




>^ 


tH 




T-l 


^ 


eg 


Csj 


^ 




eg 


eg 






-* 


eg 


CM 


CM 


eg 






c 








































o 










































1/5 


CD 


in 


CM 


in 


in 


in 


in 


c- 


in 


in 


•^ 


in 


in 


in 


in 


tn 


in 




=3 H 


'"' 




■"^ 


•"^ 


•^ 


^ 


"-• 


"-■ 


'-' 


•"I 






'-" 


'-' 












o 








































O 






































l« 


OS 


O 


CO 


tn 


c- 


o 


CO 


o 


in 


o 


eg 


CO 


c- 


o 


CD 


CO 


tn 


en 


o 


c- 


CD 


CO 


-* 


i> 


in 


-^ 


oo 


CO 


c- 


CD 

.-H 


CD 


co 


CO 


00 


eg 


t- 


CO 


__^ 






































o 


. c 






































CT) 




o 




CM 


CO 


CO 




CO 




in 


tr~ 


CO 


oo 


CO 


c- 


CO 


in 


in 










































•s 


oi 




CM 




d 


d 


d 


t-' 


d 


CO 


CO 


d 


d 


CO 


d 


in 


tr~ 


1 


CO 




■^ 


-^p 


■^ 


in 


CO 


■^ 


in 


•^ 


^ 


CO 


CO 


■^ 


CD 


•^ 


•^ 




o 






































J4 








































,^^ 






































l4 


* B 






































i 


4 


oo 




in 


CO 


CO 


CM 


<J> 


o 


eg 


OS 




in 


CO 


o 


CM 


CO 


OS 




in 




o 


o 


CO 




CO 


CSI 


in 


t- 


eg 


CD 




CD 


CO 


c- 


O 




OS 


+-<■ 


OO 


o 


"V 


cq 


in 


CO 


■^ 


o 


CO 


C- 


CO 


OS 


-^ 




i-H 


1 


0) 


l-H 




1-H 


eg 


csi 


csi 


T-* 


•-' 


eg 


eg 


eg 


'-•' 


.-; 


^ 


CM 


eg 


CM 






C 






































o 


•2 c 
2 6 


o 


CO 


CO 


o 


o 


o 


o 


CSI 


o 


o 


in 


in 


o 


o 


in 


O 


O 


o 


CO 




CM 


CO 


CO 


CO 


CO 


CM 


CO 


CO 




T-t 


CO 


CO 


CM 


CO 


CO 


CO 










































Q 










































CO 


c- 


CM 


in 


in 


C3S 


CO 


■^ 


CO 


e- 


c^^ 


•^ 


in 


oo 


o 


es] 


TP 


eg 




■**- 


CM 


CO 




CO 


CM 


CM 


•^ 


OS 


■* 


in 


•T 


T-H 


eg 


CD 


o 


CO 




'bfl 


sS 


^~* 


'"' 


'"' 


tH 


T-t 


rH 


^^ 


i-H 






'"' 




.-1 




.-H 




i-H 


*-i 








































J«S 


• 'c 






































o 
o 


II 


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218 



ADAPTATION TO ENVIRONMENTAL STRESS 



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Chapter 31 
DETERMINATION OF DISSOLVED GASES IN BODY FLUIDS 



W. F. Mazzone 
Submarine Medical Center 
New London, Connecticut 

G. F. Bond 

Special Projects Office 

Washington, D. C. 

J. W. Swinnerton 
Naval Research Laboratory 
Washington, D. C. 

INTRODUCTION 

One of the most difficult problem areas confronting the physiologist today is the lack of a 
simple, accurate means of determining the inert- gas tension in tissue. In hyperbaric physiol- 
ogy, decompression schedules may be based on mathematical calculation; however, the validity 
of such schedules can be established only on an empirical basis. Although it is common prac- 
tice to introduce safety factors in favor of the diver, it is not feasible to include contingencies 
covering all individual variations. 

This study was undertaken during the early phases of preliminary pressure exposures 
conducted at the Submarine Medical Research Laboratory, Submarine Medical Center, Groton, 
Connecticut, to determine its acceptability for a test program to be scheduled during Sealab II. 
The preliminary results were extremely encouraging, and therefore scheduled for the Sealab 
II operation. 

The application of gas chromatography for determination of small amounts of dissolved 
gases in solution, as reported by John Swinnerton, et al. of the Naval Research Laboratory, was 
considered to be the most practical means of determining the dissolved- gas levels in urine. 

The equipment consists of all- glass sample chamber in which the dissolved gases are 
stripped from solution by inert carrier, a four- way bypass valve, a commercially available gas 
partitioner, and a 1-mv recorder. Calibration for routine work is accomplished by carrying 
out the determination on a sample of water saturated with pure gas at a known temperature and 
pressure. 

The partitioner may be fitted with two columns, each containing a separate packing materi- 
al. Generally in the evaluation of respirable gases, column one contains a material called 
diethyl hexyl sebacate, which removes or retards the carbon dioxide. Column two contains 
molecular sieve 13x, where oxygen and nitrogen are separated. 

With argon gas as the inert carrier, it is possible to analyze for helium concentrations in 
urine. With argon, the sensitivity for oxygen- nitrogen separation is considerably diminished. 



Note: The introductory remarks are authored by Captains Bond and Mazzone, while the report 
itself is by Dr. Swinnerton. 

220 



DISSOLVED GASES IN BODY FLUIDS 221 

With helium at the inert carrier, it is possible to analyze carbon dioxide, oxygen, and 
nitrogen. 

During the early phases of Sealab II, it was planned to conduct chromatographic analysis 
of urine in an effort to obtain preliminary data on gas uptake. Due to logistic difficulties, this 
procedure was not considered feasible. 

During the decompression cycle, it was possible to conduct a program of urine monitoring 
each hour. 

The graphic presentation of each hourly analysis, presented in the following pages, indica- 
tes that a high correlation exists between the amount of dissolved gas in the urine and the am- 
bient atmospheric concentration. Application of this observation to decompression schedules 
is under serious consideration. 

The detailed report of this work follows. 

DETERMINATION OF DISSOLVED GASES IN BODY FLUIDS 

The objective of the work performed by the Ocean Sciences and Engineering Division, NHL, 
was the measurement of dissolved gases in body fluids. In particular, measurements were to 
be made of the rate at which the concentration of dissolved gases in body fluids responds to 
changing pressure conditions experienced by the Sealab divers. Studies were to be made of the 
rate of helium uptake immediately after descent into the atmospheric enviroment of Sealab and 
of the rate of elimination of helium and nitrogen during the decompression stage. The latter 
study is of particular importance, because the rate of gas elimination determined the optimum 
safe rate of decompression. 

An analytical technique utilizing gas chromatography, developed at NRL for the determina- 
tion of dissolved gases in liquids, was used to determine helium and nitrogen in blood and urine 
of the Sealab divers. Two Fisher Model 25 gas partitioners were used in this work. One em- 
ployed an argon carrier gas with an activated charcoal column and was used for helium deter- 
minations. The other chromatograph used helium carrier gas with a molecular sieve column 
and was used for N2 determination. The method has been described in detail in various publi- 
cations [1, 2, 3]. 

Special plastic syringes were developed for obtaining urine samples under high pressure. 
Fig. 94 is a picture of one of the syringes used in Sealab. The main body of the syringe is 2 in. 
O. D. and 1 in. I. D. The length of the plastic housing is 5 in. One end is fitted with a Swagelok 
quick connector. The plunger is made of brass or aluminum and has O-ring seals. Four 
screws pass through the back flange of the syringe; these screws with nuts are used to prevent 
the plunger from backing out when the external pressure is reduced. When filling the syringe 
with urine, the plunger is removed and the barrel is carefully filled. The plunger is then fitted 
into the barrel. All bubbles are expelled through the quick connector, and the plunger is 
pushed in until the four screws protrude through the back flange. The nuts are then tightented 
with a small wrench. The above procedures all take place in Sealab, or the deck decompres- 
sion chamber (DDC). The syringe was then sent topside for analysis. The syringe quick con- 
nector was then fastened to its couterpart quick connector, which was attached to the sampling- 
valve inlet of the stripping chamber. The urine was then forced into the sampling loop of the 
valve and immediately injected into the stripping chamber. While this method works very well 
for sea water or any liquid at one atmosphere, some shortcomings were evident when injecting 
samples under pressure. This problem will be discussed later. 

A modified Hamilton glass syringe was used for blood analysis. A Hamilton luer lock two- 
way valve was used on the front end of the syringe. The plunger has a Chaney adaptor modi- 
fied with an aluminum stop to retain the plunger in position under pressure when the syringe 
was sent topside. The plunger was also fitted with an O-ring to insure a leak-tight fit. The 
blood was heparinized to prevent clotting. Blood samples were injected through a serum cap 
directly into the stripping chamber. A sampling program for obtaining blood and urine from 
the Sealab subjects was arranged by Captain Walter Mazzone, MSC, USN (Physiological Mea- 
surement Officer), for both the helium uptake and elimination studies. 



222 



DISSOLVED GASES IN BODY FLUIDS 




The uptake studies were to be run on the subjects as they entered 
Sealab, and were to be followed for 24 hours or until helium saturation 
was reached. Samples of blood and urine were also to be taken in Sea- 
lab daily on arising. Three subjects would each given one urine and one 
blood sample. These samples would be analyzed for helium and nitrogen 
to establish a base line of helium saturation and also to serve as a 
starting point for the decompression studies. The elimination studies 
were to be run during the decompression, which would take place on the 
staging vessel in a deck decompression chamber. In Table 16 are 
listed the various studies run on all teams and the number of samples 
obtained in each. 



Table 16 
SEALAB II ELIMINATION STUDIES 




Fig. V4. Special 
plastic syringe de- 
veloped for taking 
urine samples un- 
der high pressure 
during Sealab II 



Team 


Study 


Type and Number 
of Samples 


Urine 
(He) 


Urine 
(N2) 


Blood 
(He) 


1 


Uptake 

Base Line (In Sealab) 

Decompression 


None 
38 
24 


None 
None 
None 


None 

18 
None 


2 


Uptake 

Base Line (In Sealab) 

Decompression 


5 

5 

31 


None 

1 

20 


1 

None 
2 


3 


Uptake 

Base Line (In Sealab) 

Decompression 


None 

8 

50 


None 

5 

46 


None 

6 
None 



OUTLINE OF HELIUM UPTAKE STUDIES 

No uptake studies on Team 1 were planned, since their time, during 
the first 24 hours was spent in setting up and checking out various pieces 
of equipment. This activity included the sample-pot transfer system, 
which was not in operation until the second day. 



Three men from Team 2 were to enter Sealab about five hours before Team 1 was to enter 
the personnel transfer capsule (PTC) for their transfer to the DDC. The PTC was a pressur- 
ized underwater "elevator" which was used to transfer the Sealab divers from the habitat to the 
DDC. These men would participate in various physiological tests, one being the helium uptake 
studies. Samples of urine were to be taken every two hours for about 24 hours and blood every 
three to four hours. A similar schedule was planned for Team 3. 

BASE-LINE RESULTS 

The results of the base-line studies are listed in Table 17 and are averages of all the sub- 
jects who gave samples over the 15-day period in Sealab. 



HELIUM AND NITROGEN ELIMINATION STUDIES 



These studies were performed on Teams 1,2, and 3 during their respective decompres- 
sions, which required about 30 hours each. Four subjects were to provide urine and blood 
samples. Two subjects would give two urine samples each and alternate with the remaining 
two. Both helium and nitrogen gas would be followed each hour during the decompression. One 
blood sample, to be taken every three hours would be used for helium studies. 



DISSOLVED GASES IN BODY FLUIDS 



223 



Table 17 
SEALAB II BASELINE STUDIES 



Team 


Dissolved Gases, ml/1 
(Avg.) 


Urine 
(He) 


Urine 
(N2) 


Blood 
(He) 


1 
2 
3 


45.0 
48.0 
49.0 


15.0 
20.0 


44.3 
47.0 



RESULTS OF DECOMPRESSION STUDIES 

The most reliable and complete data were obtained during the decompression studies of 
Teams 2 and 3. Decompression studies on Team 1 were not started until approximately half- 
way through their decompression, since at the same time efforts were concentrated on Team 2 
uptake studies. When it became evident that no worthwhile uptake data were going to be ob- 
tained on Team 2, it was decided to switch to Team 1 decompression. The helium and nitrogen 
decompression data obtained on Teams 2 and 3 agreed very well with the partial pressure of 
helium and nitrogen recorded at the various stages of decompression. 

Decompression of Team 2 

Fig. 95 relates to the decompression studies on Team 2. The upper part of Fig. 95 is a 
plot of the absolute partial pressure of inert gases in the atmosphere versus the decompression 
time in hours. The total pressure in Sealab was approximately 6.8 atmospheres, and the com- 
position of the major gases was02 - 7.9 percent, N2 - 14.2 percent, and He - 77.9 percent. In 
all habitats, i.e., Sealab, PTC, and DDC, the percentages of O 2, N2, and CO2 were measured di- 
rectly by gas chromatography, and helium was determined in all cases by difference.* 

A urine sample was taken just before the divers left Sealab. No samples were taken while 
the divers were in the PTC, which was approximately one hour. The total absolute gas pres- 
sure in PTC was decreased from 6.9 atmospheres in Sealab to 6.6 atmospheres, at which time 
the men transferred to the DDC. Deck decompression was started at this time. The first ur- 
ine samples from the DDC were obtained about two hours after entry. Decompression contin- 
ued at a steady rate for ten hours (see point A, Fig. 95). At this time it was determined that 
the O2 level was higher than desired. It was decided to purge the DDC with helium in order to 
reduce the O2 level. This also resulted in a reduction of the Nj level. The helium level of 
course increased during this time. After a total of 30 minutes for helium purging, decompres- 
sion was resumed. After approximately 23 hours (point B, Fig. 95) another hold was instigated 
for the purposes of sending in a medical team via the outer lock of the DDC. This step resulted 
in an immediate loss of helium and similarly an increase in the N2 level, as the outer lock was 
compressed to 2.3 atmospheres with air. Decompression was resumed, and after 32 hours the 
DDC was flushed with air. 

In the lower half of Fig. 95 is plotted the concentration of inert gases in ml/liter for ur- 
ine versus the decompression time in hours. Comparison of the changes in partial pressure 



*The gas mixture percentages and total pressures used to compute the absolute partial pres- 
sures seen in Figs. 95 and 96 were supplied by the personnel of the New London Medical Re- 
search Laboratory, U.S. Naval Submarine Base, New London, Connecticut. 



224 



DISSOLVED GASES IN BODY FLUIDS 



with the corresponding changes in gas concentration in urine shows that the loss in inert gases 
by the body closely follows the reduction in partial pressure of the inert gases in the chamber. 




15 20 

TIME IN ODC (HOURS) 



25 



Fig. 95. Sealab II, Team 2 inert-gas elimination during 
decompression; A - helium purge reducing nitrogen con- 
centration and increasing heliunn concentration, B - outer 
lock pressurized with air, increasing nitrogen concentra- 
tion and decreasing helium concentration 



Decompression of Team 3 



Fig. 96 presents results of the decompression studies on Team 3. These results are less 
dramatic than those of Team 2, since a steady continuous decompression was followed for 26 
hours. The first urine sample after Team 3 entered the DDC was taken about two and one-half 
hours after entry. In comparing the upper halves of Figs. 91 and 92 it should be noted that the 
partial pressure of N2 in the DDC was initially higher for Team 3 than for Team 2. In fact, at 
all stages of decompression for Team 3 the N2 level was greater than that of Team 2, and sim- 
ilarly the helium partial pressure was less. The lower half of Fig. 96 is a plot of the concen- 



DISSOLVED GASES IN BODY FLUIDS 



225 



tration of dissolved inert gases in ml/liter for urine versus the decompression time in hours. 
Again, the inert gases in urine decrease with time and follow very closely the corresponding 
decrease in partial pressure of inert gases in the DDC. Urine sampling was terminated 26 
hours after start of decompression, since one of the divers was experiencing slight pain and in 
fact had developed a case of decompression sickness. The remaining nine divers were trans- 
ferred to the outer lock of the DDC and were brought to surface pressure separately. No sep- 
arate medical lock was available in the outer lock for transferring urine samples, so no further 
analyses were possible. 




15 20 

TIME IN DDC (HOURS) 



DISCUSSION 



Fig. 96. Sealab II, Team 3 inert-gas elimination 
during decompression 



As mentioned previously, the most reliable data were obtained during the decompression 
studies on Teams 2 and 3. The primary reason for this was that the divers were under closer 
supervision of the support personnel while in the DDC. Another factor was the ease with which 
samples could be transferred from the DDC to the support people via the medical lock. 



226 DISSOLVED GASES IN BODY FLUIDS 

From a physiological point of view, Fig. 95 is the most significant. Both Figs. 95 and 96 
show a continuous decrease of inert gas concentration in urine with a corresponding partial 
pressure decrease. Referring to Fig. 96, it is obvious that the rate of inert-gas loss from the 
body paralleled decreasing partial pressure of inert gas with time. This in itself is significant, 
in that it is the first time such measurements have been made. The question to be asked is: 
could the rate of inert-gas losses from the body have paralleled the decreasing chamber gas 
pressures if the rate of decompressions were greater than 0.18 atmosphere per hour, which 
was maintained in this experiment? In order to ascertain if a higher rate of decompression 
could be used, one would not want to use human subjects, but instead animals should be used. 
These studies should be performed in chamber experiments. 

In Fig. 95 the most interesting point occurred at 11 hours after the start of decompression 
(see point A). As pointed out earlier, this was the time at which the chamber was flushed with 
helium in order to reduce the oxygen content. Helium purging took about 30 minutes. It is in- 
teresting to note that the time required for the dissolved nitrogen to reach its lower level (at 
15 hours) was approximately three hours from the end of the purging time. In this time inter- 
val the dissolved nitrogen decreased from 15 ml/liter to 5 ml/liter. This 10 ml/liter loss of 
dissolved nitrogen is to be compared to a loss of only 2 ml/liter during a similar three-hour 
period in Fig. 96. In the same three-hour period, the absolute partial pressure of Nj for Team 
2 decreased by 0.45 atmospheres. For Team 3, however, the absolute partial pressure of N2 
decreased only 0.15 atmosphere in the same time period. 

A short comment should be made concerning the base-line results reported in Table 17. 
The values reported in this table show a close similarity in dissolved helium concentration in 
the blood and urine. This result may be significant for Team 1, where a total of 38 urine 
samples and 18 blood samples were taken. The statistical average deviations for these sam- 
ples are ±10 percent. It is probably fortuitous that the results of Team 3 are similar to Team 1 
(that is, with blood concentrations being less than the corresponding urine samples for each 
team) . 

Helium-uptake studies were not practical, because of the lack of an adequate sample- 
transfer system from Sealab to the support vessel topside. Samples were transferred with 
specially designed pressure pots. These pots were heavy, bulky, and required two subjects to 
swim out from Sealab (putting on and taking off wet suits each time), use block and tackle to lift 
pots into Sealab, unload and load pots with samples, and then repeat the procedure to return 
samples to the surface. Consequently the divers were reluctant to send pots up with only one 
or two small samples. It is felt that a better and simpler transfer system, possibly a pneu- 
matic tube, could be used for small samples. It is also felt that a study of helium uptake could 
be performed best in a chamber experiment with the aid of a medical lock, such as the one used 
during the decompression studies. 

One of the major faults with the present plastic syringes was the ease with which helium 
diffused into and out of the plastic of the syringe barrel. This was first observed after a few 
days of using the syringe. A syringe came up from Sealab for analysis but was temporarily 
misplaced. It was analyzed 24 hours after coming topside. Previous samples had been averag- 
ing about 45 ml/liter He, while this sample contained only 28 ml/liter. For the decompression 
studies, this diffusion problem was minimized as the syringes were locked into the DDC until 
needed. They were filled and immediately locked out. The sample was analyzed usually within 
20 minutes. In future experiments all-metal syringes will be used. This defect certainly ac- 
counted for some of the scatter in results, particularly at the greater pressures. Another 
major factor contributing of the scatter was poor sampling technique on the part of the divers. 
Many syringes came up with large gas bubbles in them. It is felt that much more reliable data 
could have been obtained in this study if the subjects had been better indoctrinated and made 
cognizant of the importance of their participation in this specific area. 

The introduction of urine samples into the valving system of the chromatograph also will 
require modification. When the syringe quick connect was attached to the valve quick connect, 
the pressure was immediately reduced inside the syringe. Small bubbles formed due to the 
pressure reduction; however, the sample was immediately injected into the loop, so it is felt 
that any gas loss was at a minimum. Some refinements should be made, particularly in view of 
the fact that future experiments will be at greater depths and consequently at higher pressures. 
Modifications are presently being made which will allow the introduction of the sample into the 
loop at the pressure at which it was taken. No bubble formation can occur under these 
conditions. 



DISSOLVED GASES IN BODY FLUIDS 227 

REFERENCES 

1. J.W. Swinnerton, V. J. Linnenbom, and C. H. Cheek, "Determination of Dissolved Gases in 
Aqueous Solutions by Gas Chromatography," Analytical Chemistry, 34: 483-485 (1962) 

2. J. W. Swinnerton, V. J. Linnenbom, and C. H. Cheek, "Revised Sampling Procedure for 
Determination of Dissolved Gases in Solution by Gas Chromatography," Analytical Chem- 
istry, 34:1509 (1962) 

3. V. J. Linnenbom, J. W. Swinnerton, and C. H. Cheek, "Evaluation of Gas Chromatography 
for the Determination of Dissolved Gases in Sea Water," Trans, of Joint Conference and 
Exhibit of Marine Technology Society, Vol. 2, 1009-1032, 1965 



chapter 32 
SERUM ENZYME STUDY AND HEMATOLOGICAL DATA 



W. F. Mazzone 
Submarine Medical Center 
New London, Connecticut 

and 



G. F. Bond 

Special Projects Office 

Washington, D. C. 



SERUM ENZYME STUDY 



The development of pathophysiological responses of the body to hyperbaric environments 
has not as yet been subject to extensive study. Over the past few years, increasing interest has 
been generated in the use of oxygen under hyperbaric conditions. In the study of physiological 
responses to increased oxygenation, it appears that biochemical responses of cellular activity 
must be given further consideration. The opportunity to study enzymatic response under high 
ambient pressure in an artificial gas environment can be provided only in prolonged exposures 
such as are available in Sealab operations. Thus, in an effort to increase the background data 
of physiological responses to other than normal atmospheres, it was decided to include a pre- 
liminary study of the serum enzymes associated with those organ systems of the body which 
would most likely be effected. 

Enzymes 

A. Lactic dehydrogenase (LDH) 

B. Serum Glutamic Oxalacetic Transaminase (SGOT) 

C. Serum Glutamic Pyruvic Transaminase (SGPT) 

Method 

Physiological sampling under conditions of open-water tests are extremely difficult. On the 
basis of past experiences, it was deemed advisable and more logical to conduct a selected test 
program of blood sampling. Thus, in addition to the continuous monitoring of vital signs (Fig. 
97) it was decided that blood studies would be conducted on three individuals of Team I, and 
two individuals from Team 2. Since Team 3 was to be concerned with salvage projects, physio- 
logical testing in this case was to be minimal. 

Enzymes may be determined specifically, and when studied simultaneously, may provide 
valuable information relative to the organ system of the body which may be involved. 

Limits 

A hyperbaric experiment conducted in open water is obviously subjected to many variables 
which affect end results. It is recognized that certain factors which may affect enzyme response 
have not been identified or evaluated in this limited study. 

228 



SERUM ENZYME STUDY 



229 




MEAN BODY TEMPERATURE 



Fig. 97. Sealab II, Team 1 vital signs 



Findings 

The normal values accepted for this study have been taken from a publication by the Bureau 
of Medicine and Surgery, which indicates standards for the U.S. Naval Medical School Clinical 
Laboratory. 

Lactic Dehydrogenase (LDH) (Fig. 98) 

Normal range: 200 to 700 units 

The three subjects from Team 1 show a definite increase above the upper limits of normal 
value at about days three to four, returning gradually to within normal ranges by the end of the 
first week. 



The two individuals from Team 2 remained within normal limits. 



230 



SERUM ENZYME STUDY 



AUG. SEPT. 

30 31 I 2 3 4 5 6 7 8 9 10 I I 




TEAM I LDH -MEAN 



UPPER LIMIT 
.NORMAL RANGE 







TEAM I 



SGPT - MEAN 



TEAM 



SGOT- MEAN 



PPER LIMIT 
NORMAL RANGE 




/UPPER LIMIT 
I NORMAL RAN( 



NGE 



Fig. 98. Sealab II, Team 1 serum enzyme 
study (daily means) 



In general, the values obtained from subjects during the second week of exposure remained 
on the high side of the mid-normal range. 

One subject (SC) studied in Team 1 was continued in the second team, and it is of interest 
to note that during the second two-week exposure, all values were in normal limits. 

Serum Glutamic Pyruvic Transaminase (SGPT) 

Except for a very brief statement relative to a single above-normal finding for one subject 
on day two, no other individual exceeded the upper limit. The SGPT values do appear to be in 
the high normal range, and oddly enough, seem to bear an inverse relationship to LDH levels. 
Low LDH levels, which appear around day nine, are paralleled by high SGPT levels. 

One member of Team 2 demonstrated an elevated SGPT which persisted for approximately 
three days. On day four, this individual's SGPT fell to within normal ranges, and for the bal- 
ance of the run approximated the trends shown in a plot of Team I's enzyme levels. 

Serum Glutamic Oxalacetic Transaminase (SGOT) 

Except for one subject from Team 1 who started with an elevated SGOT level which per- 
sisted for five days, all values were within normal limits. The low SGPT level was noted on 
day eight, one day preceding the high SGPT and low LDH levels. 



DISCUSSION 

The role of selected enzyme assay in the evaluation of physiological responses to environ- 
mental stress is far from clear at this time. In addition, the intercorrelation of the enzymes 



SERUM ENZYME STUDY 



231 



selected for the Sealab 11 study cannot be evaluated at this time. Currently available techniques 
which permit stratification of some enzymes— hence offering a clue to the organ system involved- 
could not be utilized during Sealab 11; hence our enzyme data are incomplete and permit little 
interpretation. Nevertheless, it is certain that careful enzyme studies, together with the more 
classical steroid and catecholamine determinations, should yield vital information in this impor- 
tant field of severe environmental stress. 

HEMATOLOGICAL DATA 

For the purpose of obtaining necessary hematological data during the operation, venous 
blood samples were drawn from three preselected team members of Team 1, and from two team 
members of Team 2 (Fig. 99). Team 3 was not utilized for these particular studies. Samples 
were taken at a frequency of at least every other day, and immediately transferred topside for 
analysis. This transfer involved transport via a large pressure pot, with attendant difficulties 
and inevitable loss of some samples. The total number of samples received intact, however, 
was considered adequate for valid interpretation. 



SEPTEMBER 
13 14 15 16 17 18 19 20 21 22 23 24 25 



50 



i45 
40 



ir~T — r 



1 — I — I — I — I — r 

MID RANGE 




MEAN HEMATOCRIT TEAM 2 

Fig. 99. Sealab II, Team Z hematocrit 
study (daily means) 



Basically, analysis of the blood samples fell into two categories: blood chemistry determin- 
ations and conventional examination of the formed elements of the blood. 

The blood-chemistry determinations included non-protein-nitrogen and urea nitrogen values; 
blood sugar; all serum electrolytes; calcium; phosphorus, and creatinine determinations; and, in 
the case of team three, extensive carboxyhemoglobin and added carbon monoxide studies. 

The data obtained from the conventional examination of the formed elements of the blood 
are discussed below. 

Red Blood Cells 

The red-blood-cell study for Teams 1 and 2 show very little of significance. The blood-cell 
count remained within the normal range of 4 to 6 million cells per cubic millimeter, with an av- 
erage count of approximately 4.5 million. Team I seemed to pealc at approximately nine days, 
where Team 2 remained at about 4.5 million cells until day eight, when all values began to in- 
crease toward five million. 



White Blood Cells 



The white-blood-cell study for Teams 1 and 2 fell well within normal limits, though falling 
between mid and upper normal range limits. Except for one excursion above the upper normal 
limit by one individual over a three-day period, all values for Team 2 samples fell within mid 
to upper normal limits. 



232 SERUM ENZYME STUDY 

Normal limits have been taken as five to ten thousand cells per cubic millimeter. 

Sedimentation Rate 

Two subjects in Team 1 remained within normal sedimentation limits throughout the bottom 
stay for Team 1, while one subject went above the upper normal limits on two occasions, once 
at about six bottom days and once on day 15, possibly as an aftermath of a sculpin sting received 
on the previous day. 

Except for one elevated sedimentation rate on day ten for one subject, all rates for those 
sampled in Team 2 remained within normal limits. The normal sedimentation rate has been 
established as to 9 millimeters per hour (Wintrobe). 

Hemoglobin 

Hemoglobin ranged from 13 to 15 grams percent for Team 1 and from 12.5 to 15 grams 
percent for Team 2. If hemoglobin content is considered to be normal at 14 to 18 grams per- 
cent, then in Team 1, only one subject remained essentially below normal throughout the run, 
and one subject in Team 2 made one excursion to a low of 12.5 grams percent. 

The data obtained are not sufficient for statistical analysis. 

Hematocrit 

The hematocrit values for Team 1 appear to be within normal limits, generally around mid- 
range. The hematocrit picture for Team 2 appears to be concentrated in the second week. The 
significance of high normal ranges is not completely understood at this time. 

Platelets 

The platelets for both teams appear to be well within normal limits, though once again. 
Team 2 is on the high normal side of midrange. 



chapter 33 
PHYSICAL FITNESS TESTS 

R. E. Sonnenburg 

U.S. Navy Mine Defense Laboratory 
Panama City, Florida 

INTRODUCTION 

The Sealab living quarters permitted unrestricted physical motion. Comfortable bunks 
were provided for sleeping. Food was available in wide variety and ample quantity. Daily ac- 
tivities consisted of donning rubberized suits, swimming, performing light to moderate under- 
water tasks at various depths above and below 205 ft, and doffing the swimming gear. The wa- 
ter temperature was 50° to 55 °F. and caused shivering and cold discomfort which was relieved 
by a hot shower in the Sealab cabin. 

The Sealab crew was divided into three teams of 10 men each. Each team stayed in the 
Sealab n undersea habitat for two weeks. Members of Teams 1 and 2 reported subjective sen- 
sations of fatigue and lassitude which seemed to impair their work performance capacity. 
Since the work tasks were neither standardized nor measured and the physiological responses 
were not recorded, the extent of the fatigue problem could not be ascertained. Thus it was de- 
cided to study the daily physical fitness changes of Team 3 during its duty period in Sealab. 

METHOD 

Physical fitness was monitored by a test in which the heartbeat rate and pulmonary venti- 
latory rate was measured before and immediately after a barbell lifting exercise. Prior to the 
test program, the individual stood erect while his nose to deck distance was measured. The 
exercise procedure consisted of raising and lowering a special 37-lb barbell from the deck to 
nose level and return at the rate of 30 cycles per minute for a period of one minute. The ca- 
dence of the exercise was controlled by an observer who used a watch sweep second hand to 
pace the rate of the exercise. The exercise was performed in a steady, rhythmic manner and 
the observer coached him to go "faster" or "slower" as his rate of exercise declined below or 
exceeded one cycle per two seconds. 

The exercise test was performed each evening, excepting one instance (ME), between 2000 
and 2100 hours. This test time was placed at the end of daily work activities in order to detect 
fatiguing effects of the tasks or the environment, if such occurred. 

Heartbeat rate was counted for 30 seconds while the subject stood quietly before the exer- 
cise and again immediately after the exercise. The observer used a stethoscope placed over 
the apex of the heart and a watch sweep-second hand to count the heartbeat rate. The 30- 
second count was multiplied by 2 and the frequency per minute thus calculated was recorded. 

The pulmonary ventilation rate was counted and timed by a second observer who placed 
the back of his hand about an inch below the subject's nostrils in order to detect the incidence 
of respiratory flow. A 30-second count was multiplied by 2 to obtain the frequency per minute 
of the ventilatory rate. The ventilatory rate was recorded before and immediately after the 
exercise. 



233 



234 PHYSICAL FITNESS TESTS 

RESULTS 

The data from the seven subjects are presented in Table 18. The pre-exercise heartbeat 
rates and ventilatory rates either declined (SH,SO,ME) or remained fairly constant (CO, BU, 
LY, WE) during the 9 days of the tests in Sealab. The response to the test exercise was un- 
changed in all subjects except two (SH, CO) who showed some reduction in post-exercise heart- 
beat rate when the first two and last two test scores are compared. 

DISCUSSION 

From these data it may be concluded that exercise tolerance did not deteriorate during 9 
days in the Sealab n environment. If fatigue was present it was either not of the type, or not of 
sufficient magnitude to affect physical work performance. 



PHYSICAL FITNESS TESTS 



235 



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236 



PHYSICAL FITNESS TESTS 



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chapter 34 
EEC AND EKG OBSERVATIONS IN SEALAB II 

C. W. Sem-Jacobsen 

Gaustad Sykehns 

Oslo, Norway 

INTRODUCTION 

High-pressure-oxygen toxicity, anoxia, and nitrogen narcosis produce marked changes in 
behavior and in the electroencephralographic record. Minor changes in the EEG are seen as 
early warnings. 

The purpose of the present study was to determine if prolonged submergence (15 days) in 
an artificial atmosphere of He, O 2, N 2, 205 ft below the surface of the sea would cause perma- 
nent or transient physiological or pathological changes in the brain, and study an correlation 
between such changes and fluctuation in the environment including the gas mixtures. 

The experience with biological recordings from free-swimming divers in the ocean or in a 
habitat at 200 ft depths is very limited, and a number of expected and unexpected artifacts were 
encountered in Sealab II. If proper precaution was not taken, gross artifacts due to air bubbles 
from the respiration or movement in the salt water were encountered. In the same way salt 
water would through internal shorting to the body, short out the electrodes more or less com- 
pletely. Artifacts due to the movement in the ocean as an infinite body moving in the earth's 
magnetic field were also encountered. The electrical signals generated by the waves against 
the bep.ch were of an order of 10 millivolts. Electrical potentials generated by magnetic storms 
over Indonesia propagated through the ocean, and arrived at the location of Sealab H between 
1700 and 1800 in the early evening. 

These latter potentials would in the EEG recordings give slow-wave artifacts similar to 
those generated by some brain tumors or unconsciousness. Muscle artifacts were only a minor 
problem in the recording. 

RESULTS 

A number of good recordings were obtained from free-swimming divers in the ocean and 
the aquanauts inside Sealab H during the operation. The number of records obtained during 
the operation were limited, and the results are therefore given with some reservations. 

Recordings from aquanaut R show a marked increase of the alpha-frequency after he had 
been in the habitat four to six hours (Fig. 100). On the staging vessel on Sept 12, when the 
electrodes were attached the frequency of the alpha activity was 10-11 cps. In the habitat that 
first evening about 2000 the activity was up to 14-15 cps. The next evening, Sept. 13, it was 
down to 13 cps, and two days after he went down, on Sept. 14, his alpha was back to 11 cps. 

During the same period there were some marked changes in the gas mixture at the time 
of recording as reported by Dr. Larson. 

CO2 O2 N2 PSI absolute 

Date (Percent) (Percent) (Percent) pressure 

Sept. 12 0.056 5.51 21.6 100.8 

Sept. 13 0.02 4.60 22.0 100.0 

Sept. 14 0.05 4.20 21.9 100.8 

237 



238 EEG AND EKG OBSERVATIONS 




PRE DIVE, SEPT. 12 IN SEALAB., SEPT. 12 Og 5.5% 



— 'A<| *'^M*^1vv-»~*u#Ji/VW»'^^ 



SEPT. 13 02 4.6% SEPT. 14 O2 4.2% 

^ 10 SECONDS ^ CAL. = 50^V 

Fig. 100. Increase in Alpha frequency of EEC during Sealab II dive period 



The changes in the alpha frequency may be due to acclimatization. They coincided with 
subjective difficulty with the problem-solving tasks and mental confusion reported by some 
participants. 

The changes in the EEG coincided also with fluctuation in the gas mixture in the atmosphere 
in Sealab. The role of O2 in this respect is not clear, but will be studied further. 

In parallel with changes in the alpha frequency, there appeared during the initial dive per- 
iod, expecially the first 24 hours, a marked increase in paroxysmal activity in the EEG which 
diminished and disappeared by the 14th of September. This observation needs further volida- 
tion due to insufficient artifact control. The changes are, however, in conformity with the 
change one would expect from recordings during O2 or CO2 toxicity and recordings during in- 
fluence of N2 anesthesia. 

Even with a low N2 content in the atmosphere, the body's normal excretion of N2 through 
the lungs may be transient impaired, resulting in a transient N2 or narcotic effect. 

The result of the findings indicates that it will be possible to use the EEG to verify physi- 
ological compatible atmosphere in the habitat at the bottom of the ocean, as well as in free- 
swimming divers. The problems of the most compatible atmosphere for free -swimming divers 
are still of major concern. 

INSTRUMENTATION 

The Vesla biological recorder was used for recording EEG and EKG. In cooperation with 
Scripps Institution of Oceanography (Dr. Snodgrass and Mr. Hill) the instrumentation was mod- 
ified, and a special high-pressure container was built for the equipment. The housing tolerated 
seven atmospheres of pressure in salt water, as well as in a helium atmosphere. The Vesla 
equipment was in the sealed container kept under one atmosphere pressure, thus avoiding any 
complication from "the bends" in the ink system. 

A standard type S-J airborne EEG electrode v/as used for pre-descent recordings of se- 
lected members from Teams 1 and 2, as well as for the recordings from the same subjects 
inside Sealab II during the initial dive period. The same electrodes were also used for the 
preliminary EEG recording in the decompression chamber and in Sealab II. 

To obtain good records from free-swimming divers in the ocean, and in Dr. Scholander's 
salt-water tanks, the electrodes and the surrounding skin surface were isolated by a special 



EEC AND EKG OBSERVATIONS 239 

technique. For the ascent in the decompression chamber specially developed snap-on elec- 
trodes were used. 

Compatibility with telemetery system for EKG used in Sealab n was studied, and will be 
incorporated in the recording system. 

PROGRESS AND MATERIAL 

Neurophysiological investigations were carried out in close cooperation with Dr. Laverne 
Johnson of the EEG Department of the Balboa Naval Hospital, where preliminary EEG tracings 
were made from all the members of Teams 1,2, and 3. 

Dr. Scholander at Scripps Institution of Oceanography made his tanks available to one 
team for preliminary technical testing and for calibration of the instrumentation. Additional 
recordings were made from free-swimming scuba divers in the ocean. 

A total of 18 records was made from free-swimming scuba divers in the salt-water tanks 
and the ocean. 

Subjects for these recordings were members from the Sealab teams, and volunteers from 
the Scripps Institution of Oceanography - all competent divers who also gave valuable informa- 
tion about their experiences during the tests. 

The records were made in the decompression chamber, and two records were made inside 
Sealab n with all electrical systems and equipment turned on. This was done before the actual 
operation started, to make sure that no artifact would be encountered from the environment. 
Members of Dr. Sem-Jacobsen's team were subjects for these later recordings. 

Finally ten records were made in the laboratory to test out the quick recording technique 
used for the recording of EEG in the decompression chamber during the ascent of Team 1. 

On the day of the descent into Sealab II four members of Team 1 and five members of 
Team 2 had EEG and EKG electrodes attached to their heads and chests. Using the Vesla mini- 
aturized unit, a preliminary EEG and EKG record was made on the staging vessel before sub- 
mergence. To obtain the maximum number of recordings from Sealab, the Vesla unit was 
shuttled back and forth between Sealab and the staging vessel as frequently as possible during 
the first initial four days of the dive period for both Teams 1 and 2. 

Nine preliminary recordings were made from the members of Teams 1 and 2 on the stag- 
ing vessel, and 18 recordings were obtained from inside Sealab 11 during the initial dive period. 

RECOMMENDATIONS FOR FUTURE STUDIES 

1. In addition to pre and post dive recording, EEG should be recorded on permanent equip- 
ment inside Sealab. 

2. Biomedical monitoring should include EEG recordings from free-swimming divers. 
This may easily be operational on the basis of experience from Sealab n, and with some fur- 
ther homework in Norway during this winter. The Norwegian Navy has given free use of their 
facilities for this work. 



Chapter 35 

NEUROLOGICAL, EEG, AND PSYCHOPHYSIOLOGICAL 
FINDINGS BEFORE AND AFTER SEALAB II 

Laverne C. Johnson and Michael T. Long 
U. S. Navy Medical Neuropsychiatric Research Unit 
San Diego, California 

INTRODUCTION 

Neurological, EEG, and psychophysiological examinations were obtained before and after 
Sealab 11 to determine possible changes resulting from prolonged exposure to a hyperbaric en- 
vironment. The psychophysiological variables included heart rate, respiration rate, skin re- 
sistance, and finger plethysmogram. The postdive examinations were completed 12 to 36 hours 
after decompression. No significant predive or postdive neurological or EEG changes were 
found. While marked individual differences were found in the psychophysiological variables, 
the only significant difference was a drop in arousal level from predive to postdrive. 

While the laboratory findings of Genesis E (Workman, Bond & Mazzone [1], Lord, Bond, 
& Schaefer [2], Bond 1964 [3] and the data from Sealab I indicated that man could exist and 
perform useful tasks in a hyperbaric environment, Sealab n was the most stringent test to 
date of man's ability to live in the sea. The potential hazards of this unusual environment are 
many, but of primary concern for this report are the neurological hazards of diving and the 
neurological and psychophysiological effects of prolonged exposure to unusual concentrations 
and pressures of gases. 

The neurological problems posed by decompression, air embolisms, inert-gas narcosis, 
and oxygen toxicity have been summarized by Gillen [4, 5]. The effect of high partial pressures 
of inert gases on EEG and measures of performance have been reported by Bennett & Glass [6] 
and Bennett [7]. Under hyperbaric conditions they found subjects were less efficient on 
problem -solving tasks and that alpha blocking to stimuli was absent. 

The effect of varying ambient pressures and varying gas mixtures on psychophysiological 
variables has not been extensively studied. The only known report is that of Weybrew, Green- 
wood and Parker [8] who studied three subjects during a 12-day exposure to an atmosphere of 
helium, oxygen, and nitrogen. Outside of a general indication of arousal in two of the subjects, 
no definitive conclusions could be drawn from this small sample. 

As part of the pre and postdive examinations of the divers participating in Sealab II, neuro- 
logical, EEG, and psychophysiological data were recorded. During Sealab 11, three teams of 
ten men spent 15 days 205 ft below the ocean's surface. One of the participants spent 30 con- 
tinuous days in the habitat, and a second participant spent 30 days in two 15-day periods, inter- 
rupted by a period of 15 days. The Sealab environment consisted of the following atmosphere: 
temperature 82 to 88° F, humidity 60 to 80 percent, pressure 6.8 atmospheres, and the average 
composition of the major gases was oxygen 4 to 5 percent, nitrogen 21 to 22 percent, and 
helium 73 to 75 percent. As the postdive examination could not be performed before 12 to 36 
hours after the decompression, it was not expected that transitory changes, if present at all, 
would still persist. Our examinations were oriented toward determining if there were any 
changes that might be chronic. Recordings of EEG activity during the dive for Teams 1 and 2 
were done by Dr. Carl W. Sem-Jacobsen (Chapter 34). 



240 



PHYSCHOPHYSIOLOGICAL FINDINGS 241 



PROCEDURE 



All but foul- of the 28 subjects were evaluated at the research unit at some time between 9 
and 59 days before diving. The postdive examinations were done from 12 to 36 hours after 
completion of approximately 30 hours of decompression. In addition to the neurological exam- 
ination, EEG and autonomic variables (heart rate, HR, respiration rate, RR, finger pulse re- 
sponse, FPR, galvanic skin response, GSR, and basal skin resistance) were obtained. The 
autonomic variables were scored for basal levels, spontaneous fluctuations in basal activity, 
and response to stimuli. The methods of recording and scoring these variables have been 
previously reported (Johnson (9, 10). 

The pre and postdive neurological examinations included assessment of the cranial nerves, 
motor system, sensory system, cerebellar function, gait, and station, and they also included a 
screening test for aphasic signs. The subjects were also asked to subtract 7 serially from 
100, repeat numbers both as read and in reverse, name the five most recent presidents and 
vice-presidents, and interpret two proverbs. 

During the EEC, each subject was stimulated by means of a Grass Model PS-2C photic 
stimulator from 5 to 20 ops and asked to breathe deeply and rapidly (hyperventilate) for three 
minutes. The EEGs were interpreted by the neurologist as being either normal or abnormal. 
A normal EEG record was defined as having: 

1. Rhythmic and arrhythmic activity at 8 to 13 cps with asymmetry up to one-half the volt- 
age side 

2. Rhythmic beta activity regardless of the amplitude excepting focal beta 

3. Fronto-temporal theta of less than maximal alpha amplitude, occupying less than 2 per- 
cent of recording time, but no focal theta or asymmetry of more than one-half the alpha 
amplitude 

4. Variable low amplitude fast activity 

5. Any amount of drowsiness or sleep. 

RESULTS 

Electroencephalogram 

All predive EEGs during resting, waking, activation, and periods of sleep were interpreted 
as being within the criteria for normal as defined above. The postdive records were distin- 
guished by more rapid onset of sleep and the appearance of large amounts of spindle stage and 
slow-wave sleep. One subject's postdive record, because of a marked buildup of slow waves 
during hyperventilation, was read as abnormal. As this subject has not eaten in the six to 
seven hours preceding the recording of his EEG, he was brought back to the laboratory after 
fasting for some 15 hours to determine if the responses were due to hypoglycemia. The same 
response to hyperventilation was observed. He was then given 25 grams of sugar in orange 
juice. Hyperventilation 15 minutes after the ingestion of the glucose failed to produce the 
slow-wave activity. It was therefore concluded that the response to overbreathing seen on his 
postdive record was a result of fasting and not to his stay in Sealab n. 

Neurological 

Minor neurological abnormalities were found in seven individuals on initial examination. 
In five men one of the following was found: (a) alternating exotropia and difficulty intei-preting 
proverbs; (b) hyperactive left knee jerk (residual of a previous decompression left hemi- 
paresis); (c) unilateral optic atrophy with an abnormal visual field in that eye; (d) cerebellar 
ataxia of a mild degree with finger to nose intention tremor and ataxic handwriting; or (e) ex- 
tremely slow mental responses with apparent confusion. Unilateral neurosensory hearing loss 



242 



PHYSCHOPHYSIOLOGICAL FINDINGS 



was present in two men. The individual with the mental slowness and mild confusion was seen 
at the laboratory a few minutes after completing a two to three hour dive to 200 ft. A repeat 
evaluation when the diver was rested and had not been diving for a few days was completely 
normal. This diver's EEG showed an irregular pattern with dominant 4 to 7 cps activity on 
the first examination which was not present on the repeat examination. 

Neurological changes were found in the postdive examinations in only one man; marked 
improvement was noted in the man who exhibited the cerebellar findings on predive examination. 

The men were questioned in order to ascertain whether neurological symptoms were pres- 
ent while they were in the habitat. Sixteen men reported suboccipital, retro-orbital, or gener- 
alized headaches. For most the headaches were mild, but for three divers, the headache was 
so severe they were obliged to go to bed. The headaches were most severe on awakening and 
abated with activity. Three individuals reported that their thought processes were slowed, and 
two subjects experienced euphoria for the first few days. Sleep problems, getting to sleep as 
well as staying saleep, were reported by some divers. 

Psychophysiological 

Basal level values were obtained during the initial 15 minutes of both pre and postdive 
examinations. During this period, the subject was told to relax, but stay awake, and to keep 
his eyes closed. The basal levels were the average values for each of the variables during 
this period. Skin resistance values were converted to microohms and will be reported as 
conductance. Heart rate and respiratory rate variabilities were the average of the variations 
in rate from beat to beat for one minute. For skin resistance the measure of variability was 
number of GSRs occurring without any known external stimuli. A similar measure of spon- 
taneous activity was used for FPR, i.e., the number of vasoconstrictions during this 15-minute 
period which were not a response to external stimuli. 

Autonomic responsiveness was evaluated by measuring the response to the flickering light. 
The response to the first flicker as well as the average response to the 21 flicker presentations 
was scored. The flicker was presented at each frequency from 5 to 20 for 30 seconds, after a 
30-second off period between frequencies. Spontaneous GSRs and FPRs were not counted while 
the flicker was on. More complete scoring procedures are presented in the reports by Johnson. 

The pre-post basal values are listed in Table 19. Since there were no statistical differ- 
ences among the three teams on any of the predive or postdive measures, they were combined 
into one sample. As four men from Team 1 were not available for predive examination, the 
pre-post comparisons are based on 24 subject examinations. 

Table 19 
PREDIVE -POSTDIVE AUTONOMIC BASAL LEVEL VALUES 



Parameter 


Predive 


Postdive 


Significance 


Heart Rate 








Mean 


76 


75 


ns 


SD 


13.9 


14.2 


Respiratory Rate 








Mean 


15 


14 


ns 


SD 


3.9 


3.4 


Skin Conductance 








Mean 


11 


8 


.01 


SD 


3.7 


3.3 




Spontaneous GSR 








Mean 


10 


10 


ns 


SD 


6.7 


13.3 




Spontaneous FPR 








Mean 


4.9 


6.0 


ns 


SD 


2.8 


3.3 





PHYSCHOPHYSIOLOGICAL FINDINGS 243 

While there was marked variability about the mean on both predive and postdive records, 
all basal mean values were within normal limits. The predive range for heart rate was from 
48 to 107 beats per minute, while the postdive range was from 45 to 110. The same two men 
provided the minimum -maximum pre-postdive scores. This stability in pre-post heart meas- 
ures is reflected in the 0.69 (p < .01) correlation between pre-post heart rate values. For 
respiration rate the predive range was from 8 to 21 breaths per minute, and the postdive range 
was from 9 to 20. The correlation between pre-postdive respiratory rates was 0.65 (p < .01). 

Similar wide ranges were found for skin conductance and the measures of spontaneous 
fluctuation in basal values. In contrast to the significant pre-postdive correlations for heart 
rate and respiratory rate, the pre-postdive correlations for skin conductance and spontaneous 
activity were not significant, indicating marked and inconsistent individual fluctuations in these 
measures of basal variability. 

The only significant difference between the predive and postdive basal means was for skin 
conductance. The predive conductance mean was significantly higher, reflecting the higher de- 
gree of arousal before the dive. These data are consistent with the EEG findings of more 
drowsy records and quicker onset of sleep during the postdive examinations. 

Though there was a larger response in all variables to the flicker on the predive than on 
the postdive record, only the number of spontaneous GSRs during flicker was significantly 
higher. These findings, especially the GSR data, are in keeping with the difference in arousal 
level between the two examinations. 

CONCLUSIONS 

Prolonged exposure to the hyperbaric atmosphere present during Sealab 11 appears to have 
had no prolonged deleterious effect on man's central or autonomic nervous systems. Any 
changes precipitated by exposure to this atmosphere of helium, oxygen, and nitorgen under 6.8 
atmospheres were transient and no longer evident by our recording techniques 12 to 36 hours 
after decompression. 

The postdive interview data, however, suggested that some transient effects were present, 
especially during the initial period of the dive. Headaches were evidently not uncommon, some 
slowing of mental processes were reported, sleep patterns appear to have been disrupted, and 
changes in affect, i.e. euphoria, were reported. Dr. Sem-Jacobsen, while experiencing many 
technical problems in this first attempt to record EEG changes from men during the dive, did 
obtain data suggesting that EEG changes may be present and correlated with variations in gas 
pressures. 

These clinical reports and the suggestive EEG findings indicate that some detailed and re- 
liable EEG and psychophysiological recordings during the dive would be of value, especially 
during the initial periods. When compared with predive baseline data, these data could deter- 
mine the initial effects of the environment on each man. Changes in the EEG or psychophysio- 
logical variables during the dive could also be used to indicate the effect of prolonged exposure 
and possible changes in performance level. 

The wide range of predive basal values and the negative postdive findings indicate that the 
ability to adjust to atmospheres and gas mixtures such as those in Sealab n is not restricted to 
a narrow band of physiological values. It would be of interest to determine whether the predive 
data could be used as predictors of initial or prolonged response to hyperbaric environments. 
As the dives proceed to greater depths and for longer periods, the predive data may be of 
greater significance. 

The negative postdive data can be viewed as a confirmation of the results from the Genesis 
experiments and Sealab I. Sealab II further demonstrated man's ability to expand his sphere of 
aquatic activities. The lower level of arousal on the postdive examination was probably due to 
the fatigue and sleep loss resulting from the decompression schedule and demands upon the men 
for reports and interviews post decompression. The sleep difficulty experienced during the 
dive also added to the sleep debt of some of the divers. 



244 PHYSCHOPHYSIOLOGICAL FINDINGS 

As future Sealab projects try for greater depths, postdive examinations of these men will 
be of value equal to those of Sealab 11. In addition to the predive-postdive comparisons for 
each man, a comparison of changes from each Sealab project as the depths vary should be of 
interest. 

REFERENCES 

1. Workman, R. D., Bond, G. F., and Mazzone, W. F., "Prolonged Exposure of Animals to 
Pressurized Nor.nal and Synthetic Atmospheres," U. S. Navy Medical Research Laboratory 
Report No. 374, 1962 

2. Lord, G. P., Bond, G. F., and Schaefer, K. E., "Pulmonary Function in Man Breathing 
Helium, Oxygen, and Nitrogen at 7 Atmospheres Absolute Pressure for 12 Days," Federa- 
tions Proceedings, American Physiological Society, Spring, 1964 

3. Bond, G. F., "New Developments in High-Pressure Living," Archives of Environmental 
Health, 310-314, 1964a 

4. Gillen, H. W., "Neurologic Hazards of High Pressures," Clinical Application of Hyperbaric 
Oxygen, Elsevier Publishing Company, 1964 

5. Gillen, H. W., "Neurologic Hazards of Hyperbaric Oxygen Exposure," Diseases of the 
Chest 47:369-373 (1965a) 

6. Bennett, P. B., and Glass, A., "Electroencephalographic and Other Changes Induced by 
High Partial Pressures of Nitrogen," Electroencephalographic and Clinical Neurophysi- 
ology 13:91-98 (1961) 

7. Bennett, P. B., "The Effects of High Pressure of Inert Gases on Auditory Evoked Poten- 
tials in Cat Cortex and Reticular Formation," Electroencephalographic and Clinical 
Neurophysiology 17:388-398 (1964) 

8. Weybrew, B. B., Greenwood, M., and Parker, J. W., "Psychological and Psychophysio- 
logical Effects of Confinement in a High Pressure Helium-Oxygen-Nitrogen Atmosphere 
for 284 Hours," U. S. Naval Medical Research Laboratory Report No. 441, 1964 

9. Johnson, L. C, "Stability and Correlates of Spontaneous Autonomic Activity," U. S. Navy 
Medical Neuropsychiatric Research Unit Report 62-6, April 1962 

10. Johnson, L. C. , "Spontaneous Autonomic Activity, Autonomic Reactivity and Adaptation," 
U. S. Navy Medical Neuropsychiatric Research Unit Report 62-7, April 1962 



Chapter 36 
THE SEALAB II HUMAN BEHAVIOR PROGRAM 

James W. Miller Rowland Radloff 

Office of Naval Research Naval Medical Research Institute 

Washington, D.C. Bethesda, Maryland 

Hugh M. Bowen Robert L. Helmreich 

Dunlap and Associates Yale University 

Darien, Connecticut New Haven, Connecticut 

PURPOSE AND SCOPE 

The purpose of the Sealab Human Behavior Program was to make an overall assessment 
of man's behavior while living in the sea. The program was designed to study broader aspects 
of adaptation to life and work in the hostile environment and, more specifically, to determine 
how well man can perform specific tasks of a scientific or operational nature. Such informa- 
tion should be invaluable from the standpoint of planning future undersea operations, as well as 
in selecting and training individuals for such operations. 

The collection of data began in the early stages of the training period, continued throughout 
the divers' stay on the bottom, and concluded with postdive interviews, questionnaires, and 
tests, as well as continual observation of each diver's performance and interaction with the 
other members of the team by closed-circuit television. In addition, the divers' performance 
in the other scientific and salvage programs was monitored, where possible, in order to in- 
crease the validity of the overall assessment of performance. 

The members of the Human Behavior Team also assumed the responsibility for organizing, 
coding, and punching on cards, the data from many of the other programs, including salvage, 
medical, physiological, and oceanographic. As a result, the data from one program can readily 
be correlated with those of another. Because of the early deadline for this report, however, 
the results of many of the interactions will not be included. The report which follows is pre- 
liminary in nature. 

As with all field investigations, particularly those carried on in the ocean, the conditions 
under which the data were collected were less than ideal, and compromises had to be made. In 
addition to the restrictions imposed by the physical environment, equipment failures, etc., the 
Human Behavior Program was carried on under additional constraints. These included limited 
experimental time and the absence of an on-the-bottom experimenter (resulting in decreased 
planning flexibility). These comments seem to emphasize the fact that such studies cannot be 
carried out with all the checks and balances possible in the laboratory, in spite of careful 
planning. 

GENERAL METHODOLOGY 

The Human Behavior Program was planned to search for relationships between social, 
personality, and performance areas of study. As a result, the program had basically three 
components: 

1. Specific tests of visual, auditory, and psychomotor skills 

2. Observation of the performance aspects of the scientific and salvage tasks undertaken 

245 



246 HUMAN BEHAVIOR PROGRAM 

3. A careful study of how a diver carries on his work, lives in the habitat, and gets along 
with his fellow divers, utilizing the closed-circuit television and audio systems available. 

As the project developed, it became increasingly evident that it was important to establish 
the relationships between various reports, including reports made by or about the divers and 
their level of work accomplished. Achievement of this objective will permit social, personality, 
and motivational variables to be correlated with work performance. 

Standard data-gathering techniques were used in this program, including: (a) quantitative 
recording of physical measurements; (b) self-report, including standardized checkoff lists, in- 
terviews, diaries; and (c) evaluative observations, using closed-circuit television. 

DATA-COLLECTION PROGRAM 

Predive Baseline Data 

Demographic and Attitudinal Measures — These data consisted of background and baseline 
information on the aquanauts, supplied by them. The aquanauts filled out a series of paper- 
and-pencil forms, some especially designed for Sealab, some adapted from research on Ant- 
arctic groups, and some standard psychometric instruments. These forms included: 

1. Personal history booklet — largely demographic data 

2. Attitude inventory 

3. Adjective checklist — characteristics desired in a friend 

4. FIRO-B — standard test measuring attitudes toward interpersonal relations 

5. Scale of values — standard test measuring broad life goals 

6. Strong vocational interest blank — standard test of vocational and avocational interests 

7. Mood checklist — adjectives describing characteristic moods 

8. Sociometric questions — choice of most preferred leaders and teammates. 

Psychomotor Tests — About one-half of the group of 28 subjects were introduced to the 
Human Behavior Program during May and June 1965, at the U.S. Navy Mine Defense Labora- 
tory, Panama City, Florida. Some dry-land baseline data were collected on the individual 
assembly test, two-hand coordinator, group assembly, and arithmetic tests. Baseline data 
were also collected for the first three of these tests performed in shallow water (fresh water, 
70° F, at a depth of 20 ft, under exceptionally good visibility conditions). 

During the first two weeks of August, further dry-land baseline data were collected on the 
strength test, individual assembly, two-hand coordinator, group assembly, and arithmetic tests. 
Time and diver availability restrictions were such that the baseline data were some 70 percent 
complete prior to the beginning of the Sealab II submersion. 

Report forms and procedures were developed with the help of the divers. The tests chosen 
were selected in order to probe specific features of psychomotor behavior. They are adapta- 
tions of tests used in other situations. The adaptation was necessary because of the conditions 
in the water and the absence of the experimenter. It will be noted that the tests range from 
measurement of simple short-term performance to complex prolonged performance. The 
psychomotor tests required the application of maximum force, manipulative dexterity, eye- 
hand coordination, and cooperative assembly of components as outlined in the following para- 
graphs. 

Strength Tests — The purpose of this test was to determine whether there would be a 
change in exertable strength between dry-land, shallow-water, and deep-water conditions. 



HUMAN BEHAVIOR PROGRAM 247 

The test utilized two calibrated torque wrenches, one with a scale from to 800 lb, the other 
with a scale from to 1200 lb. Two strength tests were used; the lift test, and the pull test. 
The lift test consisted of bracing the feet on a platform and lifting upwards on a handle posi- 
tioned about 30 in. above the platform. The pull test was carried out by grasping the handle 
with the left hand at about shoulder height, while simultaneously grasping a grip with the right 
hand (Fig. 101). By adjusting the right-hand grip, each man could achieve a full arm-stretch 
position. In both tests, the subjects were told to exert maximum force. The torque achieved 
was recorded by a deflexion arm which moved a recording marker along a scale. 




Fig. 101. Diver performing 
strength test in shallow water 



These tests were chosen because they are representative of the actions required when 
divers are used as primary power sources, and because they provide data that are directly 
applicable to the design of hand tools. In addition, it was expected that the forces recorded in 
the lift test would be two to three times those recorded in the pull test, thus giving an appreci- 
able range in terms of muscle activity. 

Individual Assembly Test — This test measured manual dexterity and the ability to form 
spatial relationships. The test required the diver to assemble three one-foot lengths of steel 
plates into a triangle by joining the corners of the plates together with nuts, washers, and bolts. 
The divers were required to assemble each corner by placing a washer on each side of two 
lengths, pushing a bolt through the four pieces, and securing the whole assembly by screwing 
on a nut. Two bolt sizes were used: 5/32 and 5/8 in. The holes at the ends of the plates were 
placed either symmetrically (same corners), so that any end would fit to any other end, or 
asymmetrically (different corners), so that the end of one length would fit only to one end of 
one of the other two lengths. The combination of the bolt size and symmetry variables resulted 
in four forms of the test. While it was possible to assemble the symmetrical plates in any 
combination, only one manner of assembly resulted in the exact superimposition of two lengths 
at each corner. Thus, the four versions of the test varied the challenge to the subject in terms 
of the degree of fingertip dexterity required, as well as his ability to form spatial relationships. 
Performance in the water was expected to deteriorate as compared to dry-land conditions, due 
to the cold, the wearing of gloves, etc. In addition, one might expect performance to decrease 
as a result of poor visibility and general problems associated with maintaining body orientation 
with respect to work components. The test was selected as being representative of tasks re- 
quiring the assembly, adjustment, and general handling of small items of equipment. 



248 



HUMAN BEHAVIOR PROGRAM 



Two-Hand Coordination Test — The purpose of this test was to measure eye-hand coordi- 
nation. The test utilized a specially designed gear box, mounted on a stand four feet high (Fig. 
102). On two sides of this box were knobs, 2 in. in diameter. These knobs were attached to 
worm gears which produced movements in a peg protruding through the top of the box. Turning 
the right-hand knob caused the peg to move forward and backwards; turning the left-hand knob 
caused the peg to move left and right. One of nine templates could be placed on the top of the 
box. In each template a track was cut. At the start of each test, the peg was positioned at the 
end of the track. The task of the diver was to move the peg along the tracic from one end to the 
other and return in as short a time as possible (Fig. 102). The elapsed time was recorded. 
The tracks varied in difficulty; i.e., some had straight lines with right angles, others had 
straight sloping lines, while still others had curved lines, such as an S. The test was selected 
as being representative of tasks which require continuous control or adjustment of equipment, 
dynamic systems, or vehicles. 




Fig. lOZ. Diver performing two -hand 
coordination test in shallow -water 



Group Assembly Test — The purpose of this task was to observe the manner in which a 
group of four men planned and carried out a task requiring the perception of complex spatial 
reiationships and the cooperative assembly of components. The task required four divers to 
cooperate in the assembly of a three-dimensional structure utilizing short lengths of 1/2-in. 
pipe and appropriate connectors. A drawing showing the final assembly was provided to the 
divers. The divers were asked to work out a plan of attack, prior to beginning assembly. The 
time taken to execute the assembly was recorded. 

Sensory Tests — The sensory tests were chosen to gain knowledge of visual and auditory 
functions and to determine specific answers of interest to the operational Navy. For a variety 
of reasons (to be discussed later), several of the planned experiments were not carried out. 
Those tests which were conducted are mentioned below. 



HUMAN BEHAVIOR PROGRAM 249 

Audiometric Tests — Pre-exposure and postexposure hearing tests were administered to 
all divers. Hearing levels (re American Standards Association, 1951) at 500, 1000, 2000, 3000, 
4000, and 6000 cycles per second (cps) were obtained using a Rudmose ARJ-4 Bekesy-Type 
Audiometer with Otocups. The technique and equipment for all tests were identical, and the 
equipment was calibrated before and after each series of tests. Hearing levels were derived 
from the Bekesy-Tape tracings in the usual manner of accepting midpoints of the tracings and 
recording thresholds in 5-decibel (db) increments. 

Visual Tests — Although several visual tests were planned related to color, form, and light 
visibility, it was not possible to collect baseline data before submersion on these tests. During 
a predive briefing, however, the divers were shown the types of targets to be used, and the 
procedures to be followed. In addition, brightness measurements were made so as to establish 
the optical characteristics of the targets. 

Mental Ability Test — A test of mental arithmetic was given to estimate the gross level of 
mental functioning of the divers. This test consisted of multiplying a two-digit number by a 
one-digit number; zero's, fives, and multiples of eleven were excluded. The task was to com- 
plete as many items as possible in a two-minute period. Laboratory and chamber studies have 
shown that mental arithmetic is affected by narcosis. It was desirable, therefore, to ascertain 
differences between dry-land data and data collected during submersion. 

Data Collected Inside Habitat During Submersion 

1. Mood checklist — A self-report of moods filled out every other day. 

2. Daily activities checklist — A self-report of eating, sleeping, and recreational activities 
filled out each day. 

3. Sortie reports — Specially designed report forms were provided to the divers on a daily 
basis to enable them to report in detail on their activities during each sortie into the water. 
These forms were filled out in the habitat following each dive or during the evening. The forms 
had three main parts. Part I required the subject to state the plan of his dive and, when he did 
not complete the plan, the reasons preventing completion. Clothing, equipment, and tools used 
also were noted. Insofar as feasible, this reporting was done by means of a checklist. Other 
insertions in this portion of the form included the name of the "buddy," exit and reentry times, 
diving depth, and conditions encountered in terms of visibility, temperature, and bottom state. 

Part II provided space for reporting the objective results of the various tests the diver 
performed. Part III required the diver to estimate the difficulty or ease of any task he under- 
took during the sorties; his personal state in terms of a strong or weak continuum; and whether 
the task required him to be active or passive. In addition to these scales, the divers were en- 
couraged to comment in writing on their diving experience. 

4. Arithmetical tests — The arithmetical tests described in the preceding section were ad- 
ministered three times during the period of submersion; at the beginning, near the middle, and 
at the end. 

5. Helium speech data — Although a helium atmosphere has long been known to have a 
marked effect on speech, little systematic data have been collected. With the advent of under- 
water living, it is imperative that we study this problem from the standpoint of gaining a better 
understanding of the underlying mechanism, and to provide information for the design of com- 
munication systems. With this in mind, periodic samples of conversational speech were re- 
corded in the surface monitoring station, utilizing the open mikes strategically placed inside 
Sealab. In many instances, the signal-to-noise ratio was extremely low, due to ambient Sealab 
noise, and/or noise generated by the communication system itself. Therefore, specified sen- 
tences and word lists were read directly into a tape recorder inside the habitat during the pe- 
riods of relative quiet. It is planned subsequently to analyze the speech content of these tapes. 
In addition, subjective data were obtained during interviews and with questionnaires as to 
speech intelligibility in the habitat. 



250 HUMAN BEHAVIOR PROGRAM 

Data Collected in Water During Submersion 

To fully understand the data on the performance measures in the water, it is important to 
keep in mind that the Sealab II Project was not undertaken solely for the purpose of testing hu- 
man performance capabilities. 

The plan for diver participation during each team's 15-day submergence period called for 
each diver to do each psychomotor test at least once, and for a pair of divers to do one of the 
tests every other day. It also was planned that when a test measuring strength or manipulative 
ability was used, it be carried out at the beginning and at the end of a sortie. It quickly became 
apparent that this plan, or any plan, calling for a systematic accomplishment of the test, could 
not be implemented. The pressure of events, unforeseen circumstances, malfunctioning of 
equipment, and the necessity for putting the safety of the divers before every other considera- 
tion, rendered the following of any fixed schedule impossible. Under these conditions, it was 
decided to gather some data on all of the tests, even though the observations from any one test 
would be small in number, and unsystematic with respect to who did the test, and when. 

While the amount of material collected overall was considerable, it is much broader than 
deep. We may thus expect to see the emergence of a pattern of effects, rather than the pre- 
cise testing of individual cause-and-effect relationships. 

In addition to the tests on which data were collected, plans and preparations were made to 
conduct additional tests. These tests and the reasons for their lack of success will be described 
later in this report. 

Psychomotor Tests — The following four psychomotor tests are those on which data were 
successfully collected. In each test the apparatus and general experimental procedures were 
those described in the Predive Baseline Data section of this chapter. Any modifications of the 
procedures will be noted. 

Strength Test — The two torque wrenches were mounted on the habitat at the end of the 
shark cage. While performing the test the diver stood on a platform approximately two feet 
above the bottom. The data were recorded by the divers and later transferred to the Sortie 
Report Form described earlier. This test usually was done at the beginning or the end of a 
sortie. 

Individual Assembly Test — This test was performed using a platform, mounted on the end 
of the habitat shark cage, designed to be at working height while standing on the bottom. Due 
to the arrangement of lights, however, the test sometimes was done on top of the shark cage. 
This latter situation, coupled with the fact that the habitat had a six-degree list in two direc- 
tions, made the task more difficult than anticipated. In spite of these obstacles, the divers 
were able to perform the task successfully. 

Two-Hand Coordination Test — The gear box described earlier, with its supporting stand, 
was located on the bottom about 15 ft from the shark cage. The procedure was followed as 
planned. Due to technical difficulties with the automatic timer, the divers' watches frequently 
were used for timing the performance. 

Group Assembly Test — This test, due to scheduling difficulties, was only performed once. 
The plan of attack was worked out inside the habitat. The actual assembly took place in the 
water using the platform attached to the shark cage. 

Visual Tests of Form and Color — The purpose of the Form/Color Test was to measure 
detection and discrimination of form and color underwater. Many operational situations re- 
quire a swimmer to distinguish form and color. In addition, future underwater communication 
systems may require the use of shape and color. For these and other reasons, it was thought 
desirable to take advantage of the Sealab II program and collect data at depths greater than any 
worked at previously. Because of variations in ambient light, and the absorption and filtering 
characteristics of sea water, one cannot be sure as to whether data collected near the surface, 
say on color discrimination, can be extrapolated to greater depths. 



HUMAN BEHAVIOR PROGRAM 



251 



WHITE BLACK WHITE YELLOW 
SQUARE DISK CROSS TRIANGLE 




Fig. 103. Arrangement of Sealab U 
form/color visibility range 



Four targets were used; a white square, a black circle, a white cross, and a yellow trian- 
gle. The size, area, and experimental arrangement of the targets is shown in Fig. 103. Each 
target was mounted on the end of a piece of black channel iron. A specially marked surveyor's 
tape was layed on the bottom, so that the zero end of the tape was directly in front of the line 
of targets. The test was conducted as follows. Two divers swam to the 48-ft mark on the sur- 
veyor's tape, faced the line of targets, and proceeded to swim slowly toward them. The task of 
the divers was to note independently at what distance they could detect the targets, and at what 
distance they could positively identify the form. Extreme care was taken not to kick up the mud 
on the bottom. The tests were taken far enough from the habitat that only ambient light fell on 
the targets. The observations were made at various times of the day, ranging from 10:00 in 
the morning, until 6:00 in the evening. Most of the observations were taken around noon. Six 
different observers were used in this experiment. A total of 20 observations on each target 
was obtained. 

Visibility Studies — The Sealab 11 program provided one of the few opportunities to collect 
data on the optical characteristics of sea water simultaneously with human visual data. Each 
diver was required to estimate the distance at which he could see the lights of the habitat, as 
well as individual diving lights. 



An Inshore Water Clarity Meter, developed by the Scripps Institution of Oceanography, was 
used during the submergence of Teams 2 and 3. This is an instrument for measuring scalar 
irradiance and the attenuation coefficient at sea. The instrument can produce profiles of sca- 
lar irradiance at depths to 500 ft. During Sealab II it was lowered by cable to a depth of 180 ft. 
The data, which include a measure of incident light falling on the surface of the sea, is auto- 
matically recorded. Whenever possible, readings were taken during the same time intervals 
that visibility and form/color discrimination tasks were performed. This test is of great im- 
portance, as it is the first time that perceptual measurements have been made concurrently 
with optical measurements underwater. The results of such tests should enable us to predict 
more accurately visibility ranges for operational purposes from measurements made using a 
Water Clarity Meter alone. 



252 HUMAN BEHAVIOR PROGRAM 

Topside Audiovisual Monitoring During Submersion 

This program consisted mainly of recording behavior in the habitat observed on TV or 
sounds heard over the open microphones in Sealab. Television and audio signals were moni- 
tored 24 hours a day for the entire study. These data included: 

1. Order of arising — Observation of when and in what order men got up. 

2. Meal recording — Record of who prepared each meal, when each man ate, and who 
cleaned up. Attempts were made to judge mood and activity during meals. 

3. Location record — Taken every half hour. A record of where each man was and what 
he appeared to be doing if on camera. Activity and mood were also rated. 

4. Activity record — A frequency count of the number of times each man moved on and off 
one of the cameras. Recorded for one-half hour eight times per day. 

5. Laugh record — A frequency count of laughs heard over one open microphone set at a 
standard level during a half -hour period. Recorded four times per day on Teams 2 and 3. 

6. Night watch record — A recording made every 15 minutes from 2000 to 0700 hours indi- 
cating who was up and what they were doing. Other measures were suspended during this time. 

7. Log book — A running account of "significant" occurrences observed over TV or audio 
signals, or learned of in other ways. 

8. Telephone calls — A count of the number of calls made by each man each day. 



Postdive Data 

Following each 15-day submersion, the divers underwent approximately 30 hours of de- 
compression. This was followed by about a six-hour rest period and a press conference of 
1-1/2 to 2 hours. The debriefing period began at 1300 on the second day, about 50 hours after 
leaving Sealab. Three men were debriefed the first afternoon, three more the following morn- 
ing, and the remaining three or four men the second afternoon. The debriefing consisted of an 
audiometric examination, medical examinations, the completion of questionnaires, and a per- 
sonal interview. 

The members of the Human Behavior Program had the responsibility for the following: 

1. A debrief interview of each diver. 

2. A debrief questionnaire filled out by each diver. 

3. Sociometric questions — Choices of most preferred leaders and teammates. 

4. Audiometric tests — Examinations were given to each diver at times ranging from 12 
hours to 36 hours after they emerged from the decompression chamber. These tests were ad- 
ministered by the same individual, using the same equipment as for the predive test. Although 
it is recognized that there may possibly have been temporary threshold shifts immediately 
after coming out of the water, circumstances did not permit earlier examination. 

In addition to this program, data have been gathered from numerous log books of both an 
official and personal nature. Much of this data has not been analyzed at the writing of this 
report. A detailed analysis of such information should greatly increase our understanding of 
life and work in Sealab. 



HUMAN BEHAVIOR PROGRAM 253 

UNCOMPLETED STUDIES 

The scientific program of Sealab n was intentionally ambitious. It was anticipated, how- 
ever, that some of the work planned might not be successfully carried out due to constraints 
imposed by the situation in general and by the physical environment in particular. Further- 
more, most of the experiments were being attempted for the first time in an operational situ- 
ation. For this reason, the following accounts of experiments, which were not completed, are 
presented. In many instances the reason for lack of completion was primarily one of schedul- 
ing. It is hoped that such information may provide guidelines for future efforts of a similar 
type. 

Auditory Threshold and Localization Study 

The purpose of this study was to determine the distance at which various types of sounds 
could be heard by a diver underwater, as well as to measure his ability to localize the direc- 
tion. The sounds to be used were a 500 and 5000 cycle pure tone, a series of clicks, and FM 
chirps. The sounds were prerecorded on tape, calibrated, and fed into three piezoelectric 
hydrophones placed on the bottom. Although the sound-pressure levels had been calibrated 
previously in shallow water, the divers were unable to hear any signal at the observer's sta- 
tion. A microphone, placed at the observer's station, would not pick up the stimulus signals, 
but was able to pick up verbal instructions recorded on the tape, indicating that the system was 
working. Apparently, the 50 watts of power utilized was not sufficient. This is undoubtedly due 
partly to the high ambient noise levels caused by large generators operating on the surface, 
noises originating in the habitat, masking of sound by the diver's rubber hood, and bubbles. 

Stationary Target Array 

Plans were made to set up ten rectangular visual targets to be viewed by the divers from 
inside the habitat. These targets were to be arranged so that target 1 was five feet from the 
port window, target 2, 15 ft, target 3, 25 ft, etc. The first four targets contained four colors: 
black, white, yellow, and orange. The remainder were half wnite and half black. The purpose 
was to gather daily data on visibility and to assist divers in planning activities where visibility 
was a factor. 

The Measurement of Visual Acuity 

Specially mounted eye charts were devised to measure visual acuity. Although it was not 
anticipated that acuity would change, it was felt that when taken with the other visibility meas- 
urements, these observations would increase our understanding of visual capability underwater. 

Observation of Minute Organisms 

A special coUimated light source was obtained from the Scripps Institution of Oceanography 
for the purpose of observing the natural motions of plankton and other minute organisms in the 
water. It was intended that this unit be placed on the bottom in such a way that the light would 
point into one of the ports of the habitat. Because the light rays would be parallel, all plankton 
and other small organisms would be seen clearly silhouetted to anyone looking into the light 
from the habitat. Not only would this permit the density of the plankton to be estimated, but 
the characteristics of their motions could be studied as well. 

Television vs Human Visibility 

In cooperation with divers of the U.S. Navy Mine Defense Laboratory, it was intended to 
compare the detection and recognition capabilities of a diver with those of underwater televi- 
sion cameras. The plan called for the diver to swim toward a series of targets with his buddy 
carrying the camera. The detection and recognition ranges of the diver would be compared 



254 HUMAN BEHAVIOR PROGRAM 

with those seen on the TV monitor. The successful completion of this experiment would have 
had considerable implications, both from a standpoint of research, as well as military applica- 
tions. The lack of a suitable underwater TV camera prevented this study from being carried 
out. 

In addition to the specific problems of in-water experimentation, there were several of a 
more general nature which affected the data gathering in the topside audiovisual monitoring 
station. Some of these are described briefly below. 

1. Unavailability of subjects — The entire Sealab crew was seldom, if ever, available to- 
gether at any one place at the same time during training. This fact, coupled with inadequate 
lead time, made data collection less complete than it might have been otherwise. 

2. Communications — The marginal intelligibility of helium speech, particularly in a high- 
ambient-noise environment, caused serious difficulties with regard to monitoring communica- 
tions and conversation. Furthermore, the failure of the electrowriter, provided for the purpose 
of recording written communications to topside, meant that these data likewise were not avail- 
able for analysis as had been planned. 

3. Problems in TV monitoring — The data gathered around the clock by observing TV was 
compromised by frequent poor picture quality, plus the fact that the entrance area of the cap- 
sule was not covered by a TV camera at any time. This was the area in which nearly all prep- 
arations for dives were carried out. Extensive plans had been made to gather data on dive 
preparation, and the availability of such information would have increased greatly the knowledge 
of social interaction and problems associated with such activities. 

RESULTS 

This section, to be meaningful, should be interpreted with a clear understanding of the na- 
ture of the Sealab environment. For this reason the following comments are included prior to 
presentation of the results. 

Environmental Stresses of Sealab 

There can be little doubt that the Sealab environment was stressful. This, however, does 
not imply that deterioration in behavior as a result of the existing stresses was necessarily 
predicted. Rather, to speak of Sealab as stressful is to attempt to define the context in which 
behavior was assessed in this study. 

The following description of the Sealab II environment is intended to give to the reader a 
clear picture of conditions as they existed during this experiment. It should be understood, 
however, that the aquanauts were more accustomed to working under such circumstances. 
While these adversities may seem almost insurmountable to the average reader, they are 
viewed more as a challenge and inconvenience by the Sealab divers. 

A principal cause of stress in Sealab was the sea itself. The ocean at 200 ft is an unfor- 
giving adversary. The water was cold (46° to 50° F) and visibility was poor, ranging from zero 
to 30 ft at best. For safety reasons, slight negative buoyancy was desirable for a swimmer. 
Negative buoyancy, however, kept a man on the ocean floor, where swimming action would stir 
up fine silt, thus complicating the visibility problem. Further, by being close to the bottom, he 
was exposed to the painful stings of bottom-lying scorpion fish. Additional complications in 
the water were presented by the fact that the terrain was unfamiliar. Landmarks had to be 
learned gradually, and it always was necessary to follow lines attached to Sealab; otherwise it 
would have been quite easy to get lost. Once lost, a man away from Sealab would be at the 
mercy of his limited air supply, since there was no possibility of heading for the surface, the 
normal reaction of a diver in trouble. To surface would mean instant and certain death from 
the bends, as each man was saturated with gas at approximately seven atmospheres pressure. 
A single 40-in. -diameter hole, the entrance hatch in his habitat, was the only safe haven for a 
Sealab aquanaut. 



HUMAN BEHAVIOR PROGRAM 255 

Danger was inherent in the equipment which supplied breathing gas in the water. Both the 
Arawalt and Mark VI presented problems. The Arawak enabled a man to breathe the Sealab 
atmosphere through hoses from inside the habitat. There was the constant danger of the hoses 
fouling or kinking, cutting off a man's gas supply and trapping and holding him in the water. 
The Mark VI self-contained breathing apparatus is a delicate piece of equipment. It was sub- 
ject to a variety of malfunctions, some of which could occur without warning, such as CO 2 
buildup or malfunctions in regulator valves. The divers' wet suits also were far from perfect. 
Some fitted too losely, thereby allowing cold water to flow inside and chill the man; others 
fitted too tightly and restricted mobility. Finally, aside from the discomforts and dangers, 
there were numerous frustrations associated with work in the water. Frequently a man would 
go out to work on something he couldn't find or for which he didn't have the proper tools. 

Working inside Sealab was no picnic either. Crowded conditions in the entrance area pre- 
sented probably the most vexatious problems. The entrance area was a bottleneck in a very 
literal sense. Men crowded around in bulky and uncomfortable gear waiting to get into the 
water. There was almost no place to stow gear out of the way. The habitat sat unevenly on 
the bottom, with a list of six degrees in two directions. As a result, drawers would slide open 
or shut, objects would fall off counters, and men would walk up or down hill while leaning 
sideways. Long hours of careful preparation were required to put a man in the water, and the 
work schedule was constantly interrupted, delayed, and revised by emergencies or necessities. 
Work time far exceeded an eight-hour day. Communications with topside and within the cap- 
sule were difficult at best, due to the problems of understanding helium speech, and aggravated 
by constant background noise which rose to a level rendering verbal communication nearly 
impossible when the Arawak pumps were running. Work involving writing was made difficult 
by lack of privacy and the fact that writing surfaces were not level and extremely limited in 
space. 

Added to the inconveniences of working were the problems of living in the capsule. The 
fact that the atmosphere was 80 percent helium gave speech a "Donald Duck" quality. Helium 
also may have disrupted the human thermostat, so that men were sweating at the same time 
they felt chilled. Humidity was extremely high in the capsule. It was difficult to provide ade- 
quate air circulation, particularly in the bunk areas. This may have caused a buildup of CO2 
and CO, causing frequent headaches. Ear infections and skin rashes provided additional irrita- 
tions. Although culinary triumphs were achieved by Sealab chefs, the diet was restricted be- 
cause of a prohibition on frying. It was impossible to smoke in Sealab, and many of the divers 
were smokers. There were no relaxing drinks or family to come home to at the end of a hard 
day's work. Sleep was severely disrupted for most men by the long hours of work, high hu- 
midity, poor air circulation, and nagging physical complaints. In addition, the necessity of 
maintaining night watches further disrupted the normal diurnal cycle, and the crowded condi- 
tions interfered with all aspects of the daily routine. 

Sealab divers also endured the inconveniences and uncertainties associated with their 
roles as experimental subjects. They were poked, probed, stuck, and asked to fill out repeti- 
tious questionnaires. A multipurpose program dictated heterogeneous crews, so that men with 
wide variations in background and interests were in constant contact with one another. Added 
to all the uncertainties of a first-of-type operation were such real dangers as the possibility of 
an object being lowered from the surface caving in one of the portholes, causing instant flood- 
ing of the capsule. At the end of their stay, before emerging into the normal atmosphere top- 
side, the dangerous and boring processes of transfer and decompression remained to be en- 
dured. Despite the most careful precautions being taken, the transfer from the bottom to the 
decompression chamber on the support vessel posed the ominous threat of instant loss of pres- 
sure, and each man was aware of the possibility. Decompression involved a 30-hour sojourn in 
quarters even more cramped than those of Sealab. 

This then was the stressful environment; crowded, inconvenient, and potentially dangerous. 
The remainder of this report will be concerned with a description of the men who lived and 
worked in that environment and how they interacted with it and with each other. Analyses of 
the data are preliminary and sketchy, but they do permit tentative conclusions and indicate 
what further analyses may reveal. 



256 



HUMAN BEHAVIOR PROBLEM 



Demographic Data 

Only a few demographic variables will be listed in this report. There is still a large ar- 
ray of interest and attitude measures to be analyzed. Tables and brief comments below are 
given for the variables of age, years of diving experience, education, marital status, size of 
home town, civilian/military status, and career commitment. Breakdowns are given for the 
entire group and for each team. There were ten men on each team, but only 28 in the total 
group, since two men were in two crews. 

Age —Data on age are presented in Table 20. The numbers in the table represent the 
numbers of men in each age category. Mean age and age range is given below. 

Table 20 
SEALAB II AQUANAUTS - AGE 



Age 


All Teams 


Team 1 


Team 2 


Team 3 


20-24 


1 


1 








25-29 


4 


1 


1 


3 


30-34 


5 


1 


2 


2 


35-39 


13 


4 


5 


4 


40-44 


5 


3 


2 





45-49 


1 








1 


Total 


28 


10 


10 


10 


Mean 


35,1 


35.2 


35.9 


34 


Range 


26 


20 


12 


25 



It is perhaps not surprising that the mean age of the group is over 35 and that nearly half 



the men are in the 35-to-39 
in choosing team members, 
selection, that this group is 
nauts and the American Mt. 
mid-30 range. 



age range, since experience was one of the primary considerations 
It is no doubt for the same reason, experience as a criterion in 
simila,r to two other adventurous populations, namely, NASA astro- 
Everest climbing team. Both these groups have mean ages in the 



Although mean ages of the three teams are quite similar, there are differences in the 
range, with Team 2 having markedly less variation in age range than Teams 1 and 3. Since 
Team 3 had among its members the oldest man in the group, by six years, the mean age does 
not fully reflect how miich younger this group was than were Teams 1 and 2. 

Experience — As a group, the aquanauts averaged nearly eleven years of diving experience 
(Table 21). It is interesting to note that, while Team 3 was the youngest group, its members 
had the most diving experience. This is true despite the fact that for all team members there 
was a correlation of about 0.70 between age and diving experience. 

Table 21 
SEALAB II AQUANAUTS -YEARS OF DIVING EXPERIENCE 



Years of 
Experience 


All Teams 


Team 1 


Team 2 


Team 3 


0-4 

5-9 

10-14 

15-19 

20-29 


4 
7 
8 
8 
1 


4 

3 
3 



2 

4 
2 
2 



1 
2 
3 
3 

1 


Total 
Mean 


28 
11 


10 

9.4 


10 

9.2 


10 
12.5 



HUMAN BEHAVIOR PROGRAM 



257 



Education — Sealab aquanauts were quite diverse in educational background, with training 
ranging from less than a high school education to advanced degrees (Table 22). Members of 
Team 2 had, on the average, completed more years of school than members of Teams 1 and 2, 
although differences were not marked. 

Table 22 
SEALAB II AQUANAUTS - EDUCATION 



Level of Education 


All Teams 


Team 1 


Team 2 


Team 3 


Less than 

High School Grad. 
High School Grad. 
Some College 
College Grad. 
Advanced Degree 


3 

12 
3 
5 

5 


1 
4 
1 
3 

1 



4 
1 
2 
3 


2 

4 
1 
1 
2 


Total 


28 


10 


10 


10 



Marital Status — As can be seen from Table 23, the men in Sealab were family men, i.e., 
married men with children. It is interesting to note that the same is true of the two previously 
mentioned adventurous groups; astronauts and Mt. Everest climbers. Thus it appears that 
rather than being unencumbered by family responsibilities, the opposite is true of men volun- 
teering for assignments in adventures of this type. 

Table 23 
SEALAB II AQUANAUTS - MARITAL STATUS (AUGUST 1966) 



Marital Status 


All Teams 


Team 1 


Team 2 


Team 3 


Single 

Divorced 

Married/No 

Children 
Married with 

Children 


1 
3 

2 

22 


1 
1 

1 

7 







10 



2 

1 

7 


Total 


28 


10 


10 


10 



Hometown Size —Most of the aquanauts grew up in small towns and small cities (Table 24). 
Whether small-town lads seek adventure in disproportionate numbers is an interesting question 
worthy of study in its own right. 

Table 24 
SEALAB II AQUANAUTS -SIZE OF HOMETOWN 



Size of Community 


All Teams 


Team 1 


Team 2 


Team 3 


Farm or Village 
Small City of 5000-50,000 
City of 50,000-500,000 
Large City over 500,000 


8 

10 

6 

3 


2 
3 
4 
1 


2 
5 
1 
1 


4 
3 
2 
1 


Total 


27 


10 


9 


10 



Civilian/Navy Status — Civilian scientists and technicians and Navy divers participated in 
Project Sealab. Table 25 gives the numbers of men so categorized by team and for the whole 
group. Among the Navy men, two were commissioned officers, 10 were chief petty officers, 



258 



HUMAN BEHAVIOR PROGRAM 



and six were first class petty officers. Whether Navy or civilian, officer or enlisted man, 
every one of the aquanauts in Sealab was fully committed to his career. In response to the 
question, "In general, how do you feel about your present occupation?" all men chose the re- 
sponse, "I am strongly dedicated to a career in my present field." The unanimous answer to 
this question probably sums up as well as any battery of questions could why these men were 
in Sealab. For comparative purposes, it can be noted that the answer to this question is far 
from unanimous for men participating in Project Deep Freeze. Men of Deep Freeze include 
Navy and civilian specialists who winter over in the Antarctic. 

Table 25 
SEALAB II AQUANAUTS - CIVILIAN/NAVY STATUS 



Status 


All Teams 


Team 1 


Team 2 


Team 3 


Navy 
Civilian 


18 
10 


7 
3 


6 
4 


7 
3 


Total 


28 


10 


10 


10 



Psychomotor Tests 

Strength Test — The data comparing performance on land with that during submersion are 
shown in Table 26. 

Table 26 
COMPARISON OF STRENGTH-TEST DATA ON LAND AND SEALAB SUBMERSION 

(RECORDED IN FT-LB) 



Type of Test 


Dry 
Land 


Sealab 


Differ- 
ence of 
Group 
Means 


Mean 
Differ- 
ence 
Scores'" 


Number of 
Observations 
to Compute 
Mean Differ- 
ence Scores 


Pull 

Group 
Mean 

Number of 
Observations 

Lift 

Group 
Mean 

Number of 
Observations 


236 
ft-lb 

15 

626 

ft-lb 

15 


200 
ft-lb 

58 

606 

ft-lb 

60 


36 (15%) 
24 (4%) 


38 
25 


12 
13 



''Difference scores are computed by comparing each individual's performance on dry land 
and in Sealab when the same individual performed the test under both conditions. Twelve 
men performed the pull test both on dry land and in Sealab. Thirteen men performed the 
lift test in both locations. 



It is evident that exertable force decreased under Sealab II conditions, particularly for the 
pull test. This may reflect, in part, the difficulty of performing the test when the feet cannot 
be anchored as firmly as on dry land and, in part, the relatively greater attrition that smaller 
muscle groups may suffer due to cold as compared to larger muscle groups. In discussing 



HUMAN BEHAVIOR PROGRAM 



259 



this test with the divers following submersion, it was revealed that some of the men found it 
annoying to be required to perform the test. This was particularly true at the end of a sortie 
when they were cold and tired. As a result they occasionally vented their frustrations and an- 
noyance on the test by pulling for all they were worth. This large expenditure of energy (for 
whatever reason) may have had the effect of counteracting what might, under normal conditions, 
be a larger loss of overall strength. The fact remains, however, that the energy resources 
were available when called upon. 

It is interesting to note further that a significant positive correlation was found to exist 
between the amount of strength exerted and (a) the expressed dislike for meals, and (b) com- 
plaints about not having enough free time. These relationships lend support to the notion that 
certain men felt frustration and annoyance and that they found suitable expression both by re- 
porting their dislikes and by extreme application of themselves on the strength test. 

Individual Assembly Test — The individual assembly (triangle) test was performed on dry 
land, in shallow water, and during Sealab. Table 27 presents the group means (M) and the 
number of times the test was performed (N). The (N) does not necessarily indicate the number 
of divers who performed the test, inasmuch as some divers performed the same test more 
than once. 

Table 27 

GROUP MEANS (M) AND NUMBER OF TRIALS (N) 

FOR INDIVIDUAL ASSEMBLY TEST 

(Data Given in Seconds) 



Test Configuration 


Dry Land 


Shallow 
Water 


Sealab 


M* 


Nt 


Mt 


Nt 


Mt 


Nt 


Triangle 1 (Lg. Bolts Same Corners) 
Triangle 2 (Sm. Bolts Same Corners) 
Triangle 3 (Lg. Bolts Diff. Corners) 
Triangle 4 (Sm. Bolts Diff. Corners) 


58.7 
83.1 
77.6 
85.9 


12 
21 
12 
21 


78.5 

97.3 

87.1 

103.3 


13 
13 
13 
13 


105.2 
110.7 
108.2 
159.0 


9 

8 

10 

7 



■'Mean value. 
iNumber of tests. 

Figure 104 illustrates more clearly the overall trend of the data. The data show a 37- 
percent increase in performance time between dry-land and Sealab conditions. It also shows 
that performance time increases as a function of smaller size components and greater restric- 
tion on the number of available ways to assemble the triangle properly. It should be noted that 
success in the individual assembly task is significantly correlated with the amount of diving 
experience and significantly negatively correlated with the number of aborted missions. That 
is, the shorter the assembly time, the fewer number of aborted missions. An interpretation of 
these findings will have to await further analysis. 

Two-Hand Coordination Test — The amount of data taken on this test was less complete 
than for all other psychomotor tests due to equipment malfunctions and allows a comparison to 
be made of the three conditions of performance only for plate 5. The track on this plate was 
essentially a straight line S with a "bump." Table 28 presents a summary of the data. 

The data indicate a 17-percent increase in performance time between dry land and Sealab 
conditions. Plate 5 might be considered to be a medium difficulty. It should be of interest in 
the future to determine the relationship between level of difficulty and performance decrement, 
using some of the more difficult plates not used sufficiently in this study for valid conclusions 
to be drawn. 

Group Assembly Test — Only one group assembly test was undertaken outside the habitat. 
The time taken was 12 min, 20 sec. However, the team had practiced assembling the compo- 
nents and discussed their strategy immediately prior to going out to do the test. Hence, the 
time taken may be compared to the best time recorded by a team operating on dry land who had 
inspected the test, discussed it, and practiced it. The best dry-land assembly time was six 
minutes. There is thus prima facie indication that this type of work may take twice as long to 
do under Sealab conditions as compared to dry-land conditions. 



260 



HUMAN BEHAVIOR PROGRAM 



160 




SEALAB 



SHALLOW WATER 
DRY LAND 



I 2 3 

TRIANGLE 

Fig. 104. Meantime (in seconds) of all sub- 
jects and all trials for individual assembly- 
test (triangle 1 - large bolts, same corners, 
triangle 2 - small bolts, same corners, tri- 
angle 3 - large bolts, different corners, tri- 
angle 4 - small bolts, different corners) 



Table 28 

TWO-HAND COORDINATION TEST DATA FOR 

PLATE 5 UNDER THREE CONDITIONS 

(Data Given in Seconds) 



Test 
Environment 



No. of 
Tests 



Time to 

Accomplish 

Test 

(Mean) 



Differ- 
ence 
in 
Means 



Mean 
of the 

Differ- 
ence 

Scores 



No. of 
Divers 
Perform- 
ing Both 
Tests 



Dry Land 
Shallow Water 
Sealab 



45 

14 

6 



125.1 

144.3 
150.8 



19.2 



21.8 
Insufficient Data 



14 



Mental Arithmetic Test — As described earlier, this task consisted of multiplying a two- 
digit number by a one-digit number. The divers were instructed to complete as many prob- 
lems as possible in a two-minute period. Table 29 compares the predive results with the re- 
sults obtained in the habitat during submersion. 

Table 29 

COMPARISON OF MENTAL ARITHMETIC TEST DATA 

OBTAINED ON DRY LAND AND INSIDE SEALAB 



Performance 


Dry Land 

N* =55 


Sealab 
N= 66 


Mean Number of Problems Attempted 
Mean Number of Problems Correct 


26.49 
24.31 


30.10 
27.78 



*N is number of tests. 



The results indicate that not only was there no decrement in performance, but rather that 
performance actually improved in Sealab. This suggests that there was a practice effect (al- 
though not statistically significant) between the two conditions. These data do not demonstrate 



HUMAN BEHAVIOR PROGRAM 



261 



that there was no mental deterioration during Sealab, but only that, if there was any, it was not 
gross enough to be detected by this test. 

Visual Studies 

Form/Color Test — It will be recalled that the purpose of this test was to measure detec- 
tion and discrimination of form and color underwater. Six divers were used to obtain a total of 
20 observations on each of the four targets. Table 30 shows the mean detection and recognition 
distances. 

Table 30 

DETECTION AND RECOGNITION DISTANCES 

FOR THE FORM/COLOR STUDY 

(N = 20) 



Measured Parameter 


Targets 
(ft from subject) 


Black 
Circle 


White 
Square 


Yellow 
Triangle 


White 
Cross 


Detection 
Recognition 


24.4 
20.0 


18.3 
14.2 


16.7 
13.5 


16.5 
13.4 



It is readily apparent that the black circle is both detected and identified at greater dis- 
tances than either the white or yellow targets. This is particularly interesting when consider- 
ing that it is the smallest of the four targets in area (black disc = 707 sq cm, white targets = 
900 sq cm). The differences between the means of the black circle and the white square were 
tested using the standard t-test and found to be significant at better than the 0.01 level of con- 
fidence. The mean detection and recognition distances of the white cross and yellow triangle 
are even less than the white square. 



When one considers that visibility is a function of contrast between target and background, 
it becomes clear that the contrast of the black circle was greater under the conditions sur- 
rounding Sealab. 

General Visibility Observations —A major factor in underwater operations is visibility. 
The selection of the Sealab site was, in fact, almost changed at the last minute because of poor 
visibility. Although the experiments on underwater light visibility were not carried out as 
planned, some data were obtained during the debriefing interviews. Each diver was asked to 
estimate the maximum distance he could see a 1000-watt underwater quartz light. For Team 1 
the mean answer of nine responses was 43 ft, with a range of 30 to 60 ft. For Team 2 the mean 
answer was 60 ft, with a range of 50 to 70 ft. Team 3 had a mean of 95 ft and a range of 40 to 
170 ft. It is apparent that the general visibility was improving during the 45-day submersion 
period. 

Data were collected with the water-clarity meter during Teams 2 and 3 dives, which hope- 
fully can be related to the daily reports of visibility recorded on the sortie report form. 

All 28 divers stated that the white habitat was far more visible than the reddish-orange 
personnel transfer capsule (PTC) sitting on the bottom 15 ft away. In many cases the habitat 
was said to be visible at two or three times the distance of the PTC. 

Further studies need to be performed on underwater visibility of light and color. It must 
be kept in mind that studies in fresh water and even at shallow depths in the ocean cannot nec- 
essarily be extrapolated to greater depths. This is particularly true when selecting paint and 
coding colors. 



262 



HUMAN BEHAVIOR PROGRAM 



Tentative Findings on Overall Adjustment and Adaptation 

Introduction — In this section we will present a few tentative findings on adjustment and 
adaptation to the Sealab experience by team and by men. It is important to emphasize the fact 
that the data presented and discussed here are in a most preliminary and rudimentary stage of 
analysis. 

Three facts stand out. First, there is the general observation that, as a group, the aqua- 
nauts performed at a high level and adapted very well to their environment. Second, there 
were individual differences in performance and adaptation. The existence of individual differ- 
ences in performance does not, however, imply that some men succeeded and others failed in 
Sealab. It means simply that some men performed better than others in a situation in which 
the level of performance of all of the men was at a high level. 

Third, it seems apparent that individual differences in performance and adaptation can be 
predicted on the basis of demographic and personality characteristics of the men. Since there 
are some 12 to 15 criterion variables and 20 or more predictor variables, the analysis is ex- 
tremely complex. However, such an analysis should produce a profile of characteristics which 
predict performance and adaptation in a Sealab-like environment, as well as in other unusual 
and hazardous environments. Thus the results of this study should produce valuable informa- 
tion for selecting future personnel to participate in programs of these types. 



Team Performance and Adaptation — As mentioned previously, the best general descriptive 
statement regarding performance and adaptation is that all three teams performed at a re- 
markably high level and adapted to their environment and to each other very well. Possibly 
the best specific indication of this generalization is the fact that there was an increase in av- 
erage daily time in the water for each succeeding team. Even more indicative of adjustment 
by each team is the fact that there was an increase in average daily time in the water in the 
second week compared to the first week for each of the three teams. A second specific indica- 
tion of favorable adjustment is that team cohesiveness, as measured by sociometric choice, 
increased for each of the three teams from pre to post choices. 

In Table 31 data are presented bearing on cohesiveness. The numbers in Table 31 were 
derived as follows. Each aquanaut was asked to name in order the five men he would most 
like to have as teammates in Sealab. Each man's choices were given a weight of 5 for first, 
4 for second, etc., to 1 for fifth. For use in Table 31, these weighted choices were called 
in-group or out-group, according to whether or not the man chosen was on the same team as 
the chooser. Thus the in-group choices could range from to 150 (10 men x 15 points per 
man; i.e., 5+4 + 3 + 2 + l)x 10= 150) and the out-group choices would be the reciprocal. A 
total of zero in-group choices would mean that no one on a team chose another team member, 
while a total of 150 in-group choices would mean that all men on the team chose fellow team- 
mates for all five choices. Thus, the higher the number, the more cohesive was the team. 
Data in Table 31 include some slight correction for missing cases, since data were not obtained 
from two divers on the postexperiment measure. 

Table 31 
SOCIOMETRIC CHOICES OF SEALAB AQUANAUTS OF 
OWN-TEAM MEMBERS BEFORE AND AFTER TEST 



Time of Choice 


Total 
All Teams 


Team 1 


Team 2 


Team 3 


Pre 

Post 

Change Pre 
to Post 


147 
250 

+103 


47 
102 

+55 


27 

47 

+20 


73 
101 

+28 



HUMAN BEHAVIOR PROGRAM 263 

The numbers in Table 31 contain a wealth of interesting data for both speculation and spe- 
cific inference. First and most important is the fact that in-group choices increased for all 
three teams, indicating a favorable within-group atmosphere. There was no particular reason 
to anticipate this result, as the change could easily have gone in the opposite direction. A sec- 
ond interesting fact is that team composition appears to have been virtually random according 
to sociometric choice before the experiment. What is meant by this statement is that only 147 
of a possible 450, almost exactly 1/3, of the choices for teammates were made from within the 
teams as assigned. Thus, it appears that there was as much identification with the entire group 
of 28 aquanauts as there was for a ten-man team before the dive. A third point of interest is 
the difference in cohesiveness scores among teams. Team 1 apparently had a much greater 
increase in cohesiveness than did the other two teams. The greater increase in cohesiveness 
in Team 1 could have been due to their being the first team, that is, due to the greater stresses 
associated with initiating the system, and to the fact that there seemed to be greater similarity 
in the types of tasks performed by members of Team 1 than there was on Teams 2 and 3. 

In addition to the quantitative data regarding time in the water and team cohesiveness, 
there were other less precise indications of successful performance and adaptation. Chief 
among these indicators were comments by a number of men to the effect that work got easier 
as time went along; that there was better planning and scheduling; that they adapted to the cold 
water; the nearly universal eagerness to take part in future Sealab type studies; and the com- 
plete absence of any serious interpersonal disagreements on any of the three teams. 

Despite the overall favorable reactions indicated above, there were some ripples in this 
sea of tranquility which should be mentioned. 

Most of the aquanauts expressed dissatisfaction or disappointment with the amount of work 
they were able to accomplish. Their dissatisfaction is no doubt in part an indication that this 
was a highly motivated, task-oriented group of men. A major factor limiting work output was 
the design of the capsule, particularly the entrance area. 

Another factor was fatigue. For a variety of reasons many men had a great deal of diffi- 
culty in getting adequate sleep in Sealab. A number of men commented that while they would 
like to have stayed longer, they were ready to leave at the end of 15 days because of fatigue. 

Another work-inhibiting factor was the amount of time which had to be spent on housekeep- 
ing and maintenance chores. One change which might be considered would be either supplying 
meals from topside or including a crew member whose sole duty would be to prepare meals. 
To adopt one of these alternatives would, however, make future Sealabs more dependent on sur- 
face support than was the case with Sealab II. Finally, there was the factor of crew heteroge- 
neity. A number of men felt that others on their team either did not cooperate fully in helping 
them to perform their functions or that others had insufficient work to do while they were 
overloaded. Comments to this effect were made by the majority of divers on Teams 2 and 3. 

Association Among Predive, Dive, and Postdive Measures — Data presented in this section 
represent more a preview of things to come than they do a systematic presentation of results. 

Each diver was assigned a score representing the number of times he was chosen as a 
desirable leader or teammate. *These scores were correlated with a variety of diver charac- 
teristics and behavioral variables. There are missing data which may alter slightly some of 
the correlations presented here. 

Each man was asked to name, before and after, the five men he would most like to have as 
a leader and the five men he would most like to have as teammates in Sealab 11 or in future 



*NOTE: A comment about the significance of correlations is appropriate for understanding the 
results presented. Human behavior is so complex that nearly all interrelations involving 
measures of men and their performance are inexact and probabilistic. Therefore, rules in- 
volving the laws of probability are used to determine when a relationship exists. To say that 
a correlation is significant means that the relationship involved is of such a magnitude that it 
does exist and is not due to chance factors. All correlations reported here are significant by 
this definition, except where stated otherwise. 



264 HUMAN BEHAVIOR PROGRAM 

Sealabs. Correlations between before-and-after choices were very high, but there were 
changes. The correlation between men chosen as leaders on the predive and postdive measures 
was +0.94, while the same correlation for teammates was +0.79. It is not surprising that these 
correlations were so high in view of the previously mentioned good intra-team relations. 
Climbers on the American Mt. Everest team evidenced the same stability in predive and post- 
dive sociometric choices. The higher correlation for leader than for teammates is probably 
due to the fact that fewer men were seen as potential leaders. 

Although the correlations between before-and-after choices were high, there were changes 
in men chosen. First, there is an indication that different characteristics were used in naming 
leaders and teammates, since the correlations between predive leader and predive teammate 
choices was +0.42 and that between post leader and post teammate choices was +0.49. While 
these correlations are quite high, they do not approach the level of predive-postdive correla- 
tions on either the leader or teammate choices. 

Age was a significant variable in the choice of leader and teammate. Older men also 
tended to be preferred for leaders and teammates on before-and-after measures. As could be 
expected, the correlation between age and choice for leader is higher than that between age and 
choice as a teammate. At first glance it is somewhat surprising to see that choice as leader 
and years of diving experience are not significantly correlated. This lack of relationship, how- 
ever, is probably artificially determined by one man who was highly chosen as leader even 
though he had relatively little diving experience. Of considerably greater interest is the fact 
that there is a high correlation between years of diving experience and choice as teammate on 
the predive measure (r = +0.55), but that this correlation drops to +0.27 (not significant) on the 
postdive measure. This means that while diving experience played a large part in choosing 
teammates in the predive measure, other factors assumed greater importance as a result of 
exposure in Sealab. 

A brief look at some other variables provides clues as to what might have made the differ- 
ence in pre and post choices. There was a tendency not to choose men who complained about 
conditions in Sealab or who made frequent telephone calls from the capsule. Measures of 
complaints are taken from answers to the postexperiment questionnaire. The number of tele- 
phone calls is a straight frequency count of personal calls initiated by divers from Sealab. 
While extreme caution is necessary in attributing causative relations to such correlations, it 
does appear that men who were most satisfied and content with their lot in Sealab were the ones 
who were chosen as desirable future teammates. This interpretation is supported by the fact 
that the amount of time a man spent in the water was correlated with postdive sociometric 
choices. Finally, sociometric choices were correlated with a number of predive measures of 
mood and attitudes. Although these measures are too obscure in meaning to warrant discus- 
sion at the present stage of analysis, the existence of such relations does indicate that it will 
be possible to specify the characteristics of divers which are deemed desirable by their team- 
mates. 

Audiometric Test * —An examination of the pre-exposure data provided a basis for several 
general observations. Only four of the 28 subjects had normal hearing, conventionally defined 
as no more than 15-db loss at any of the test frequencies in either ear. Four other subjects 
had normal hearing for one ear, with below-normal hearing levels for the contralateral ear 
only at test frequencies above the speech range (3000, 4000, and 6000 cps). Five of the subjects 
had hearing loss (greater than 15 db) at one or more of the test frequencies in the speech range 
(below 3000 cps), in addition to high-frequency hearing loss. The remaining subjects (about 
half) all had high-frequency loss, with some extreme instances (up to 70 db). The average 
hearing levels for all ears (subjects combined) were within the normal range, except at 4000 cps 
and 6000 cps, but these averages are inherently deceptive, as they tend to conceal the wide 
range of individual differences. As the main interest and concern are with individuals rather 
than group data, statistical analysis of the data is not appropriate. 



'■"This test was conducted and the results analyzed by Dr. George Harbold, Life Sciences Divi- 
sion, Naval Missile Center, Point Mugu, California. 



HUMAN BEHAVIOR PROGRAM 265 

Comparisons between the predive and postdive data were made to determine any possible 
trends from the effects of prolonged pressure exposure on hearing levels. Again, a wide range 
of individual differences was demonstrated. The differences between predive and postdive 
thresholds were aggregated for all subjects and ears by test frequencies. Less than one-fifth 
of the changes were in the direction of better hearing levels. Slightly less than one-fourth of 
the threshold differences, when viewed in the same manner, showed no change between predive 
and postdive levels. In contrast, more than half of the hearing-level changes were in the direc- 
tion of hearing loss. Thus a trend toward acquired hearing loss is indicated. It should also be 
pointed out that although changes were relatively small when postdive levels showed better 
hearing (usually 5 to 10 db), the postdive hearing loss changes were more prevalent and 
greater (up to 25 db). 

The conclusions from a pilot effort such as this should be viewed as tentative, but certain 
implications are fairly obvious: 

1. Hearing levels of divers tend to reflect a pattern of acoustic trauma quite similar to 
that of personnel exposed to high-intensity noise levels. Hearing ability of divers is also sub- 
ject to additional deleterious effects from more than the usual amount and degree of ear pa- 
thologies. Therefore, the need for a program of hearing conservation for these personnel is 
indicated. 

2. The single episode of exposure to the environmental conditions of Sealab II resulted in 
very little change in hearing levels for frequencies in the speech range (below 3000 cps), but a 
trend was indicated for hearing loss at the higher test frequencies (3000 cps and above). 
Therefore, any future projects of this nature should include a more comprehensive and care- 
fully planned study of auditory functions. 

GENERAL DISCUSSION 

Psychomotor Tests 

The data at hand indicate that a general decrement in human performance occurs between 
dry-land and shallow-water conditions, and increases under Sealab conditions. The trends of 
the data indicate that short-term, simple performance, requiring little thinking and not depend- 
ent on the use of the senses to any extent (e.g., strength test) is least affected, and that com- 
plex, prolonged performance, calling on many human faculties (e.g., group assembly), is most 
affected. This differential decrement effect can be seen most clearly in the data from the in- 
dividual assembly test, where the task difficulty increases in terms of dexterity requirements 
and the need to attend to spatial relations. 

There are indications in the data, as analyzed thus far, that some part of the performance 
decrement is associated with personality variables. As previously mentioned, relative lack of 
frustration tolerance, evidenced by expressed dislikes and complaints, is echoed in high 
strength-test scores. It also appears that persons enjoying above-average choice as fellow 
team members do well on the individual assembly test. This may reflect a desire to be with 
persons who are careful and methodical in their work, virtues which would tend to be shown in 
high scores on the individual assembly test. As examination of the data continues, other rela- 
tionships of this type are expected to emerge. 

While these individual differences in underwater performance are important for the pur- 
poses of team selection, task allocation, etc., the major issue is the observation of the average 
performance decrement, particularly the sizeable decrements associated with the more com- 
plex tasks. 

Helium Speech 

The problem of verbal communication in a helium atmosphere is well known. The differ- 
ence in the density of the medium causes everyone to sound Uke Donald Duck. Upon entering 
Sealab, many divers, especially those to whom the experience was novel, found the situation 



266 HUMAN BEHAVIOR PROGRAM 

utterly hilarious. In addition to the humorous aspects, however, the voice distortion posed a 
considerable communication problem. 

This problem, to a certain extent, annoyed the divers during the entire 45 days. It often 
was difficult to communicate a complex idea or set of instructions. For regular conversation 
regarding food and equipment, however, there was a remarkable amount of adaptation. Al- 
though postdive questionnaires and interviews revealed that 23 of the 28 divers had initial dif- 
ficulty in communicating, when asked, "How soon were you able to understand all nine other 
aquanauts quite well?" the responses showed that 16 divers felt they could in one to two days, 
eight more by the end of four days, two more by the eleventh day, and one never. 

Each diver stated that the voices tended to get lower in pitch and that the rate of speaking 
slowed down. Most divers said they learned to recognize voices in two to three days. There 
always was extreme difficulty in localizing sounds due, it is supposed, to the inherent difficulty 
of locating high-pitched sounds plus the reverberation characteristics of a closed chamber. 
Several commented also that their voices did not seem to carry over two to three feet. Whether 
this was due to high ambient noise level produced by equipment or to the helium atmosphere 
was not determined. A striking example of the extent to which adaptation took place was 
brought out when three members of Team 2 entered the habitat prior to Team 1 leaving. Team 
1 members had so adapted to each other, over the 15-day period, that they were hardly able to 
understand the three newcomers for several hours. The newcomers were laughed at because 
of their "high squeaky voices." 

Although once again man's tremendous powers of adaptation were shown, there is much 
work to be done in this area. Inasmuch as men in a helium environment will always have to 
communicate with "outsiders," techniques of making the speech understandable will have to be 
developed. Likewise, future diving operations will require swimmer-to-swimmer communi- 
cation systems. For these reasons the selected word lists and phrases recorded during Sealab 
will be carefully analyzed. 

Personal Equipment 

The men spent much time in selecting and preparing their personal equipment. In some 
cases, they had little choice in the matter, while in others they had complete freedom. Two 
types of wet suits were available, in three different thicknesses: 3/16 in., 1/4 in., and 3/8 in. 
Generally, the men preferred the 3/16 or 1/4 in. suits because of greater mobility. In some 
cases the top of one suit and the bottom of another would be worn. There was no unanimous 
choice of one particular suit. The experimental heated suit used by a few divers was found to 
be comfortable and warm, but because of poor fits (resulting in cold water leaking in), was of 
limited usefulness in Sealab II. The battery packs were felt to be too large and interfered with 
various activities. This was a prototype suit, and such difficulties are to be expected. The 
suit is a big step in the right direction. 

Three different kinds of gloves were worn. Mittens were found to be warm, but totally un- 
satisfactory for doing work. Both the three-finger and five-finger gloves were used satisfac- 
torily. Preference for these gloves was about equally divided. Four or five divers never wore 
gloves because they felt they couldn't work with them. On the other hand, some of the individ- 
ual triangle assembly tasks were satisfactorily done while wearing both three-finger and five- 
finger gloves. 

The conventional hand tools (wrenches, rope, etc) were found to be satisfactory. All mov- 
ing parts had to be carefully washed and coated with permalube daily to prevent corrosion. 
Carrying tools around sometimes presented problems. Whereas one tool could be tucked in- 
side the wet suit, a diver carrying several had either to tie them on his wrist or use a bag. 
The development of multipurpose hand tools would help to alleviate some of these problems. 
Some type of coding to make it easier to find dropped tools would also be of great value. A 
dive may, at times, have to be aborted because a dropped tool cannot be found. With the advent 
of underwater living, more sophisticated jobs will be undertaken calling for more sophisticated 
tools. Collaboration between designers, divers, and human engineers should result in greatly 
improved tools and/or equipment. 



HUMAN BEHAVIOR PROGRAM 267 

Divers' Comments on the Habitat 

Whenever long periods of time are spent in a confined area, factors related to comforts 
and conveniences, workspace layout, noise levels, lighting, etc., which, for short stays, are 
hardly noticed, become annoying and, at times, intolerable. The Sealab habitat is no exception. 

The debriefing interviews and questionnaires revealed that there are many improvements 
which can be made. Each diver was asked to indicate the relative importance of a detailed list 
of improvements. No attempt will be made here to discuss each of these lists. There were, 
however, several problems of sufficient importance to affect the performance of the overall 
operation. 

The single most important problem with respect to work interference was the size of the 
entrance hatch and diving area. This area was always congested with men and equipment and 
severely hampered operations. For example, it took an average of 45 minutes to prepare for 
a dive with the Mark VI scuba rig. It took another 30 to 40 minutes to clean up after a dive. 
This amount of preparation and cleanup time for a 30 to 40 minute dive sometimes discouraged 
divers from going into the water at all. The overall result was less time in the water than 
otherwise might have been the case. 

Other serious problems were related to humidity control, air circulation, storage space, 
and noise levels (primarily due to the air compressors for the diving hose). In addition, there 
were problems concerning outside lighting, hoist and cargo-handling facilities, layout of bunk- 
room, and poor communication equipment. 

Cold Water and Visibility 

As discussed in the introductory paragraphs of the Results section in this chapter, there 
are many hostile features present when living in the ocean. Cold water and poor visibility 
were constant companions during Sealab II. When asked on the questionnaire, "Did you feel 
you became better acclimated to the outside water temperature as time went on?" of the 26 
divers responding, ten said, "Yes, quite well;" 12 said, "Yes, somewhat;" three said, "Yes, 
only slightly;" and one said, "No, not at all." During the debriefing interviews some stated that 
they felt they adapted in two to three days, while others felt they were still adapting to the cold 
even at the end of the 15-day period. Interestingly, a few said the water felt warmer at night, 
even though the thermometers did not bear them out. Many reported that their efficiency in- 
creased as adaptation took place, and that at the end they were coming back to the habitat more 
because of becoming tired than being cold. The degree of physical activity, of course, had a 
marked effect on the feeling of being cold. All in all, the problem of cold can be overcome by 
initial selection of divers, by careful planning of activities in the water, and by the continued 
development of improved heated suits. 

Poor visibility is a problem over which we have less control. The general poor visibility 
during Sealab II was of continual concern. Many of the men reported that they were constantly 
preoccupied with their own and their buddies' personal safety, especially during the first few 
days. In addition to concern over equipment, there was the ever-present danger of becoming 
lost. Tether lines or guide lines were used at all times, even though the men became familiar 
with the topography as time went on. As shown earlier, a diver's light could be seen from 15 to 
90 ft, depending upon the water clarity; the glow of the combined lights of Sealab could be seen 
even further, especially at night. Communication and signaling systems must be developed 
which will increase the confidence of divers to work a greater distance over wider areas under 
conditions of poor visibility. 

Comments on General Stress 

Many reports have suggested that the divers had short memory losses, that silly mistakes 
were made, poor planning was commonplace, and that generally there was much more confusion 
than would be expected. 



268 HUMAN BEHAVIOR PROGRAM 

It certainly is true that there was much confusion due to logistic difficulties, schedule 
changes, etc. Perhaps some of the confusion, mistakes, and memory loss was due to the 
stressful situation. It must be kept in mind, however, that prior to each dive, detailed prepa- 
rations had to be made. Each diver had to remember many things, maintain a constant vigil 
over his air supply, his location, the location and state of his buddy, etc. Furthermore, the 
lack of swimmer-to-swimmer communication means that a pair of divers have to return to the 
habitat simply to exchange a few words or plan at great length what appears to be an extremely 
simple task. 

In other words, in addition to the multitude of safety precautions there were numerous de- 
tails to contend with in an extremely hostile environment. With so much on their minds, it is 
not surprising that some things were forgotten and that in retrospect, silly things were done 
and details overlooked. An additional factor is that, in most instances, it was not possible to 
practice each operation in detail or to conduct simulation training on land. As a result, pro- 
cedures were not routine to the extent that performance was automatic. It might be mentioned 
that general observation of performance indicates that the more complex a task the greater the 
likelihood was that something would go wrong. The human-performance tasks also suggest a 
relationship between complexity a,nd poorer performance; i.e., the decrement in performance 
was least for the simpler tasks. One, therefore, must carefully temper judgment regarding 
the effects of stress with the potentially overwhelming problem of human information process- 
ing. 

Another factor to be considered is the relationship of the symptoms mentioned above and 
fatigue due partially to lack of sleep. The behavioral symptoms of sleep loss (forgetfulness, 
short-term memory loss, difficulty in planning and executing plans, etc.) are extremely simi- 
lar to those described above. During the debriefing interviews, it was found that almost all of 
the men had difficulty in sleeping. Some stated they never slept longer than 1-1/2 hours at one 
time. Previous research has shown clearly that the symptoms described above are associated 
with sleep deprivation, even in the absence of other stressful factors. It is difficult to pinpoint 
the reasons for lack of sleep at this point. Some of the most probable contributing factors were 
high humidity, constant headaches, poor air circulation in the bunkroom, high noise levels, and 
perhaps being overly tired. Subsequent analysis should permit a more thorough understanding. 

General Comments on Motivation and Morale 

The preceding sections of this report, describing the environment and working conditions, 
paint a dismal picture of Sealab U. In spite of all these adverse conditions, the motivation and 
morale of the divers was extremely high. The comments of the divers upon emerging at the 
end of each 15-day period indicated that they "were amazed that men of such diverse back- 
grounds and experience could get along so well under such conditions." 

It may be premature to attempt to answer at this stage of data analysis how or why the 
men of Sealab were able to perform and interact so well. Indeed, this question can probably 
never be answered definitely. The primary value in attempting to assess reasons for success- 
ful performance in Sealab is that it may stimulate thought and discussion and may afford a 
basis for comparison with similar situations. 

Probably chief among the reasons for the performance of men in Sealab II v/as motivation. 
The knowledge that they were part of a project with unlimited potential and great significance 
doubtless had an impact on most if not all of the men. The sentiment behind this high motiva- 
tion was probably best expressed by one of the divers on Team 1 who, upon being congratulated, 
responded, "Hell, I'm no hero, 10,000 other Navy divers would have given their right arm to 
have been in Sealab." Similar thoughts were expressed by many other divers during debriefing 
interviews. Comments such as, '11 was the greatest experience of my life," were made by 
many. Closely related to the feeling of being involved in a significant project was a real feel- 
ing of accomplishment. Despite disappointment in the accomplishment of personal objectives, 
there was the knowledge that useful work was done and invaluable information obtained in the 
face of very trying circumstances. Possibly as important as the feeling of individual accom- 
plishment was the sharing of this leeling. In talking to the individual divers there was apparent 
a sense of shared affect, of vicarious satisfaction in what the whole group had achieved. 



HUMAN BEHAVIOR PROGRAM 269 

All the divers were volunteers, a fact which probably produced a predisposition to endure 
whatever hardships came along with the feeling that, "I got myself into this and now it's up to 
me to prove that I can do the job." 

Furthermore, each diver expressed a desire to participate in future Sealab operations. 
Most of them felt, however, that they would prefer to stay down longer in the future, but that a 
crew size of six to eight would be better in the Sealab II habitat. When asked, "How many days 
do you think you could live and work in the Sealab II habitat?" the average answer was 31 days. 
One of the chief reasons given for lengthening the bottom time was that the first week was spent 
getting organized and becoming familiar with the equipment and topography. Once these goals 
were accomplished, more time and mental activity could be devoted to accomplishing the job at 
hand. 

While many felt that it would be desirable in the future to have some of the specific house- 
keeping chores assigned permanently, 22 out of 28 felt that the workday schedule was about 
right. Along similar lines, some of the Navy members of Team 2 felt they had no jobs to call 
their own and were primarily supporting the scientific personnel. In the future, it might be 
advisable either to assign specific operational tasks or to train Navy divers to work closely 
with a scientist. 

Some of the Naval personnel felt it would be much more challenging and that they would be 
motivated to spend more time in the water if the salvage projects in future Sealabs were genu- 
ine. Even though the tasks during Sealab were of an operational nature, it was not the same to 
them as actually performing a "real job." 

The men were asked to compare working from Sealab with doing a similar job from the 
surface. The response of one of the men expresses the general feeling that, "There is the tre- 
mendous advantage of being able to start a job and then finish it. Whereas, say a guy could 
drop down from the surface and maybe have 20 minutes on the bottom, he could be just two or 
three minutes away from completing the job and his bottom time would be up and he'd have to 
quit and they'd bring him up and put somebody else down." It was stated further that if operat- 
ing from the bottom, "You'd maybe take a couple of tools and go out and start on the job and 
see just what it was with the idea that, if you needed some more tools, you could pop back in a 
couple of minutes and maybe change your tools, or get a different wrench and get some more 
information and then go back out." 

Another question asked on the postdive questionnaire was, "Based on your experience, 
which of the following characteristics do you think most important for a man to live and work 
in a Sealab environment?" The possible answers are shown in the following list in the rank 
order in which they were rated by the divers. A desire to "get the job done" and general so- 
ciability seem to be the personality characteristics most valued. 

A question frequently asked of men living in an unusual environment concerns the matter 
of isolation feelings. When asked on the postdive questionnaire, "How isolated from the world 
topside did you feel?" of the 24 responding, ten said, "Not at all," niae said, "A little," four 
said, "Quite a bit," and one said, "Very much." One interesting comment during debriefing 
was, "I kept waiting for this sense of isolation, you know —where you hate everybody topside. 
I never did." 

Summary of Rank Ordering by 28 Divers When Asked for the "Charac- 
teristics You Think Most Important for a Man to Live and Work 
in a Sealab Type Environment 

1. Diving experience 

2. Willingness to do his share of general work 

3. Competence in work specialty 

4. Physical condition 

5. Sense of humor 

6. Has imagination 

7. Takes orders well 

8. Tries to keep everyone's morale high 



270 HUMAN BEHAVIOR PROGRAM 

9. Is tactful 

10. Keeps his mind always on the job 

11. Doesn't waste time or energy 

12. Ability to mind own business 

13. Previous experience working with the team 

14. Is the kind of person you could tell your troubles to if you felt like it 

15. Doesn't get too personal 

16. Age 

17. Has led the same general kind of life you have 

Although all indications are that high levels of motivation and morale are maintained, it 
must be kept in mind that the novelty of the situation may have played an important role. The 
nextiew man-in-the-sea projects may likewise have no morale problems. If, however, large 
numbers of men are to be chosen in the future for undersea operations, it is important to 
gather data on which selection criteria can be based. 

In summary, it can be stated that the team effort was a success, interest and morale was 
high, useful work was accomplished, and that much was learned that will benefit both the scien- 
tific community and the Operational Navy. 

CONCLUSIONS 

Much of the data analysis has not been completed at the time of writing this report. There 
are, however, some conclusions which can be made at this time. 

Psychomotor Tests 

1. The results of a lift and pull strength test showed a decrease in exertable strength be- 
tween dry land and Sealab. 

2. The individual triangle assembly (manual dexterity) tests reveal a 3 7 -percent decrease 
in performance between dry land and Sealab. 

3. The two-hand coordination test shows a 17-percent decrement in performance in Sealab. 

4. The three-dimensional group assembly task took twice as long in Sealab as on dry land. 

Visual Tests 

1. It was found that a black target was seen at significantly greater distances than either a 
white or yellow target at a depth of 205 ft in ambient light. 

2. It was observed that the white habitat was far more visible than the orange/red person- 
nel transfer capsule. 

Mental Arithmetic Tests 

No decrement was found between predive and Sealab tests. 

Audiometric Test 

Little change between pre- and postdive exposure tests were found in hearing levels for 
frequencies in the speech range (below 3000 cps), but a trend was indicated for hearing loss at 
the higher test frequencies (3000 to 6000 cps). 



HUMAN BEHAVIOR PROGRAM 271 

Helium Speech 

Most divers understood and recognized voices after two to three days, but had continual 
difficulty in localizing sounds inside the habitat. Speech became lower in pitch and slower with 
adaptation. 

Adaptation to Cold Water 

Although some divers said they adapted to the cold water within the first two to three days, 
many said they were still adapting at the end of the 15-day period. As expected, there were 
large individual differences in cold tolerance. 

The divers stated overwhelmingly that, if the Sealab II habitat is used again, the team size 
should be six to eight. Many felt also that specific tasks should be laid out for each man be- 
fore going down. 

Motivation and Morale 

The motivation and morale of the men was extremely high in spite of the stressful aspects 
of the situation. It is concluded that mixed teams of Navy and civilian divers can successfully 
perform useful work. It is cautioned, however, that when the novelty of being "first" wears off, 
more attention must be paid to the selection of team members. 

Overall Adjustment and Adaptation 

The amount of time spent diving increased from team to team, and within all three teams 
from the first to the second week. Group cohesiveness, as measured by the divers' choices of 
own team members, increased for each of the three teams from pre- to postexperiment meas- 
ures. That is, more men were chosen from within a man's own team post as compared to pre- 
experiment. 

There were differences between teams in original levels of cohesiveness as well as differ- 
ences in increase in cohesiveness between the teams. 

There was no evidence of any serious interpersonal difficulties on any of the three teams. 

Despite a general feeling of accomplishment, many men were dissatisfied with the amount 
of work they personally achieved. 

Correlations between pre- and postchoices of both leaders and teammates were very high, 
indicating that in general the same men were chosen as most desirable leaders and teammates 
after the experiment as before. 

There were, however, some interesting changes between pre- and postchoices, chief of 
which is the fact that number of years of diving experience was not associated with postchoices, 
whereas it was with prechoice. 

Different criteria were used for choosing leaders and teammates. Men who complained 
about conditions in the Sealab habitat tended not to be chosen as a teammate on the postdive 
questionnaire. 

In conclusion, it should be made clear that in spite of all the obstacles and dangers present 
during Sealab II, an unprecedented amount of useful work was accomplished. While some of 
this work possibly could have been performed from the surface, a diver, with his inherent flex- 
ibility for on-the-spot decision making and planning, was the essential element in the program. 
The aquanauts' performance of scientific and operational tasks demonstrates clearly that man 
can live in harmony with the hostile undersea environment. Having again demonstrated the 
tremendous ability of man to adapt, the future of undersea habitation and exploration should be 
limited only by our technology and imagination. 



Chapter 37 

ELECTRICALLY HEATED PRESSURE-COMPENSATED 
WET SUITS FOR SEALAB II 

E. L. Beckman 

Naval Medical Research Institute 

Bethesda, Maryland 

and 

H. R. Frey 

United States Rubber Company 

Wayne, New Jersey 

INTRODUCTION 

Studies on the physiological mechanisms which relate to thermal conservation of the im- 
mersed diver have been in progress at the Naval Medical Research Institute for several years. 
At the time of the inception of Sealab n, this laboratory had a contract with the Marine Corps 
to develop an insulative and supplemental heating garment for thermal protection of Marine 
reconnaissance swimmers. A prototype garment had been designed and produced on contract 
and was in the process of being evaluated at the Naval Medical Research Institute. This R&D 
program served as a basis for the development of the electrically heated, constant-volume, in- 
sulated garment which was ultimately procured for use by the Sealab 11 aquanauts. As part of 
this development for the Marine Corps, considerable work had been done to evaluate different 
types of insulative materials as to their effectiveness as thermal insulators. 

A project was therefore established at the Naval Medical Research Institute by Special 
Projects May 3, 1965, for the design, development, and procurement of electrically heated, in- 
sulative undejrwater swimmers wetsuits for Sealab 11 aquanauts. Although this time period was 
very short for a developmental program, it was considered to be sufficient for the development 
of a prototype garment for use and evaluation by Sealab n aquanauts, because most of the pre- 
liminary work had already been done, and the basic concepts of such a garment had already been 
developed. A contract was let with the U.S. Rubber Company to design and fabricate eight elec- 
trically heated, insulative, underwater swimmers wetsuits to be powered by either a battery 
pack or through a cable from a power supply from within the Sealab. The preliminary descrip- 
tion of the suit requirements defined the duration of the underwater exposure as four hours and 
the temperature of the water as between 45° and 50° F. These two parameters then defined the 
amount of thermal insulation required of the suit as well as the number of kilocalories (kcal) of 
heat to be supplied by the suit to the wearer. With these design limitations, the U.S. Rubber 
Company's inflatable insulative electrically heated wetsuit was designed and fabricated to fit 
eight of the personnel who were expected to become the aquanauts of Sealab n (Subsequently it 
was found that one of the wetsuits fitted two aquanauts). 

Four aquanauts of Team 1 were fitted with the U.S. Rubber Company's electrically heated 
underwater swimsuit (Figs. 105, 106). Unfortunately, time had not been available to indoctri- 
nate and train the aquanauts adequately in the use of these garments. Therefore, in several in- 
stances when the suits were worn by the members of this team, the gas-purging valves were 



Note: The Introduction to this chapter was written by CAPT Beckman; the balance of the chapter 
written by Mr. Frey, was originally published as the final report for Contract No. 
N600(168)63855. 



272 



WET SUITS 



273 



left open during swimming, so that the suits were flooded with seawater.* Although the aqua- 
nauts reported that they provided adequate supplemental heating, they were not operating satis- 
factorily because of the flooding of the air cavity within the suit. 




Fig. 105. Aquanaut Dowling assists Aquanaut 
Barth in donning the snag suit over the elec- 
trically heated wet suit. 



Four members of Team 2 were also fitted and provided with electrically heated underwater 
swimmer wetsuits. Three of these aquanauts had had an opportunity to be indoctrinated in the 
use of the suit and to practice using the suit in a salt-water pool, so that familiarity and con- 
fidence in the suit were obtained before the suit was used on the sea bottom. These three aqua- 
nauts found the suit to be most helpful in increasing the duration of their dives. One of these 
aquanauts used the electrically heated suit with a battery pack for a swim of 2 hr and 53 min. 
Inasmuch as the heated suit with battery power was designed to provide thermal protection in 
50° F water for a duration of 3 hr, the operational use of the heated suit for a 2 hr and 53 min 



♦Editors note — Weighting of the heated suit was accomplished by the use of inner pockets, into 
which small bags of lead pellets were placed. In the course of Team 2's submergence, one of 
the Team 2 divers became buoyant upon leaving the habitat. Only by vigorous swimming and 
aid from his diving buddy was he able to return to the habitat. The cause of the incident was 
attributed to misjudgment on the part of the aquanaut. Nevertheless, the incident emphasizes 
the need for extreme care in the design and use of gas-purging valves and the check out of 
weight requirements by the aquanauts. 



274 



WET SUITS 



period infers optimization of design. These aquanauts found the suit to be comfortable and to 
increase their time in the water significantly. No physical measurements were obtained as to 
skin or body-core temperature or oxygen utilization during these periods. 




Fig. 106. 



Aquanaut Jenkins wearing the electrically heated wet 
suit near Sealab II 



It was the consensus of opinion of the nine aquanauts who used the electrically heated 
underwater swimmer wetsuits that this type of garment was definitely useful and should be fur- 
ther developed by improvements in compactness and ease of donning. In addition, the basic 
conception of supplying supplemental heating as a method of increasing diving time in cold 
water was definitely established. 



BACKGROUND 



Recent developments in mixed-gas saturation diving have permitted man to remain sub- 
merged at depth for longer periods than ever before. The reasons for extending man's diving 
capabilities to greater depths and longer intervals are legion. The general goal is to take ad- 
vantage of the vast continental shelf areas for commercial exploitation and for military defense. 
Among the ultimate specific goals are submarine rescue, deep salvage, in situ physical and 
biological oceanographic research, oil and gas mining, mineral mining, submarine farming, and 
many more. Many of the tasks required to accomplish the military, scientific, and commer- 
cial goals will require the remarkably complex intelligence and dexterity of man rather than 
machines and instruments. To perform these tasks with maximum efficiency, man needs to be 
provided with modern diving equipment. 

The developments in diving equipment have not kept pace with the relatively recent develop- 
ments in diving medicine and physiology that have led to projects such as Sealab EC. Saturation- 
diving techniques enable man to remain submerged for periods of weeks rather than minutes or 
hours as before, but he must face the severe demands of the underwater environment with 



WET SUITS 275 

equipment that hardly satisfies the modern requirements. Emphasis has only recently been 
put on the need for research, design, and development of equipment that will enable man to 
operate effectively in the depths along the continental shelves. 

One of the most severe problems facing the modern diver is maintaining the thermal bal- 
ance of his body is an environment which is essentially a cold and infinite heat sink. A com- 
parison of the heat capacity and thermal conductivity of water versus air indicates that the 
subsurface environment is indeed a tough adversary. Body-heat loss is a relatively rapid proc- 
ess in cold water unless ample thermal protection is afforded the diver. The problem is by no 
means a new one. It has been with us since the early days of diving. Only the operational re- 
quirements have changed as diving activities became more diversified. Today, the problem is 
acute mainly because exposure times have been increased by orders of magnitude. 

fflSTORY 

The need to insulate the human body to reduce heat loss to the water is obvious and has 
been appreciated for many years. But the supply of heat to supplement the body's heat produc- 
tion has received very little attention. Electrically heated underwear for surface- supplied 
helium-oxygen diving was developed during the late 1930' s. Technological problems left much 
to be desired, and the heated underwear was barely acceptable. Until recently, no attempt was 
made to provide a heated, insulated garment for other forms of diving and underwater swimming. 

A study of prolonged immersion in cold water has indicated that supplemental heating is 
essential for thermal balance. Insulation alone will not suffice. The physiological problems, 
analyses, and recommendations for solutions can be found in reports by Beckman, et. al. [1, 
2, 3J. 

Evidence to support the concept of supplemental heat in an insulated garment is also given 
in these reports. The development of heated suits for Sealab 11 was based partly on the argu- 
ments set forth in CAPT Beckman' s study. 

The development of protective garments for divers and swimmers was not a new one for 
the U.S. Rubber Company. The history of such work within the company dates back long before 
the beginning of World War 11. The Clothing Department, part of the Consumer Products Divi- 
sion, has pioneered the development of various types of diver's and swimmer's dress and has 
had substantial experience in fabricating such products. Developments were sporadic, however, 
because interest and funding existed only to solve immediate problems with dispatch. There 
has been very little long-term research and development by any organization in this field. 
Prior to the work reported here, the most recent development by the Clothing Plant was a 
pressure-compensated wet suit for the 432-ft saturation dive made by Stenuit and Lindbergh in 
1964. The concept of such a suit was established to be worthwhile, even though there were 
technological problems, of the type that always seem to be associated with an accelerated 
schedule. 

The Research Center of the U.S. Rubber Company began to examine the problem of cold- 
water immersion during 1963. New concepts in protective garments were sought. Novel meth- 
ods for insulating and heating divers were studied. It became apparent that thermal protection 
for long exposures would require new approaches and modern technology. A team of specialists 
was formed, drawing on personnel from various departments within the U.S. Rubber Company 
corporate structure. 

The work reported here is the result of a negotiated contract issued on the basis of "Tech- 
nical Proposal to Perform Research, Development, and Testing of Electrically Heated Hydro- 
naut's Suits for Sealab II." The government's request for this proposal followed from a more 
general and extensive unsolicited U.S. Rubber Company proposal. Much of the groundwork for 
the heated-suit development was performed in-house prior to the contract. 



276 WET SUITS 



OBJECTIVES 



The principal technical objective was to evaluate the concept of an electrically heated 
pressure-compensated wet suit under actual operating conditions. The concept of supplemental 
electrical heating in a non-pressure-compensated suit had already been established in the lab- 
oratory by the Naval Medical Research Institute. Another important objective was to provide 
thermal protection for Sealab II aquanauts, with the view of increasing their useful work time 
in the water. One of the earliest objectives was to survey the various means of providing sup- 
plemental heating and pressure-compensated insulating material and to make selections based 
mainly on the most expeditious design and hardware procurement. The overall objective of the 
program was to accomplish a first step in the development of an electrically heated pressure- 
compensated wet suit. 

STATEMENT OF THE PROBLEM 

The problem, as stated in the negotiated contract, was to: "Provide the necessary research, 
development, and engineering tests, as required, to supply electrically heated garments for use 
in maintaining thermal comfort of underwater swimmers operating in water of down to 40° F. 
and at a depth of 320 ft for periods of up to four hours. This procurement shall include both the 
insulative garment with electrical heating system incorporated and battery power supply so as 
to provide approximately one (thermal) kilowatt hour as required by the swimmer. The rate 
shall not be more than 350 watts. The garment shall likewise be designed to have power sup- 
plied through a 100-ft power cable so as to permit heating the suit from a power source within 
the Sealab n compartment or other source. Four cables and four sets of batteries are to be 
supplied." 

Eight experimental suits were to be delivered on or before Aug. 31, 1965, allowing only 
eleven weeks for the contract program. The main problem was in the time frame of the pro- 
gram rather than in some technological aspect of the work. A request was made to accelerate 
the schedule even more and to deliver the suits on Aug. 7. This was done. 

PLAN OF THE REPORT 

The technical discussion in this report features mainly the highlights of the program. De- 
tailed technical information is given for some aspects of the work. Both negative and positive 
results of materials evaluation are discussed, with the hope that such discussion will be benefi- 
cial in reducing the amount of repetitive effort by other investigators. Suit prototype fabrica- 
tion details are not given extensively, because much of that information is proprietary. The 
technical discussion includes research, design, development, prototype fabrication, training and 
field engineering, evaluations, malfunction analysis, and recommendations for further work. 

RESEARCH 

Review of Physiological and Physical Concepts 

The approach to thermal protection taken during the program reported here was based in 
part on the findings of Beckman, et al. [1, 2, 3]. 

Regional heat losses from the fingers, hands, and arms have been shown to result in an 
increased reaction time, a decrease in tracking proficiency, a decrease in manual dexterity, 
with a loss of tactile discrimination and kinesthetic sensation, as well as a decrease in muscle 
strength (4). Severe body-heat loss can result in degrees of hypothermia, with various symptoms 
such as amnesia, loss of contact with one's surroundings, pain, loss of voluntary motion, and 
cardiac irregularities (5, 6). Factors which can be used to limit the loss of body heat during 
cold water immersion are (1): 

1. Controlling the duration of the period of immersion 



WET SUITS 277 

2. Utilizing the body's own thermal protective mechanisnas to maximum advantage 

3. Use of adequate external body insulation to limit heat loss 

4. Use of supplementary body heating to replace the heat loss. 

Control of the exposure duration imposes a serious limitation on the useful work time of 
both military and commercial divers. This approach is impractical and, in some cases, im- 
possible. The second factor, utilizing the body's own thermal protective mechanisms to max- 
imum advantage, can contribute relatively little to the thermal-balance problem. Cold-water 
tolerance by training and/or conditioning has only limited value. 

External insulation and supplemental heating are the only two body-heat-loss factors con- 
sidered [l]. Insulation alone cannot satisfy the thermal requirements, because of the adverse 
geometries of the hands and feet. It is necessary to replace body heat to provide thermal sta- 
bility for immersed subjects. On the other hand, supplemental heating alone is not the answer, 
because of the severe power requirements it would impose on a portable power pack. A com- 
bination of effective insulation and supplemental heating of critical areas is a logical engineer- 
ing approach to cold-water thermal protection. 

For the interest of the reader, the reports by Beckman, et al. [l, 2, 3] include detailed in- 
formation about the physiological processes and problems, references to thermal protection 
for Arctic troops and for aviators, a summary of power-source and heat release methods and 
hardware, and a list of 21 references. 

Delimitation of Technological Research 

The accelerated-program schedule dictated that applied research be limited to short-term 
work. Studies carried out inhouse prior to the contract award made it possible to select re- 
search tasks on the basis of maximum probability of near-future results. Of the numerous ap- 
proaches to thermal protection, the electrically heated pressure-compensated wet suit was 
selected as the best candidate for rapid development. This approach was specified in the con- 
tract. Power efficiency of the self-contained power source was a major criterion in determin- 
ing the heating system. Another major criterion was the need to perform only minor develop- 
ment to off-the-shelf hardware for the integration of components. Power efficiency and hardware 
availability indicated the use of silver-zinc batteries, resistance wires for heating, commer- 
cially available gas and underwater electrical fittings, and an insulating sandwich material 
which had already been developed to an advanced degree by U.S. Rubber Company. 

INSULATING MATERIAL 

The need to provide constant buoyancy and thermal insulation regardless of the depth in- 
dicated the use of an insulating material which would either be incompressible or capable of 
being pressure-compensated. Both approaches were investigated. Foremost among the re- 
quirements for the insulating material was low stretch modulus, to provide adequate diver mo- 
bility in a form-fitting wet suit. 

Pressure-Compensated Insulation— Open-cell foamed elastomers were reviewed as candi- 
dates for a pressure-compensated insulating material. Natural rubber latex foam was chosen 
above all others for its low modulus of elongation, high rebound, low compression set, small 
and uniform pore size, behavior at near-freezing sea-water temperatures, and relative ease of 
fabrication into a laminate. Relatively thin elastometric skins on both sides of the foam layer 
were required to serve as water-impermeable membranes. 

The skin material research included natural rubber, neoprene, and butyl latices. Despite 
the severity of ozone -cracking, natural rubber latex was chosen for the same reasons (except 
pore size, of course) as given above for the selection of natural rubber latex foam. The skin 
material was formed by latex-dipping methods and was applied to the latex foam. 



278 WET SUITS 

It was important to avoid using any substances in the insulating material which would cause 
toxicological effects. Such effects could be quite hazardous, as the diver's body is nearly com- 
pletely covered by the material. The compounds used were screened for toxicological effects 
by a company toxicologist prior to being used in the garments. 

Natural rubber is particularly susceptible to surface cracking due to ozone in the atmos- 
phere. Such cracking originates when the rubber surface is strained either statically or dy- 
namically. Static ozone-cracking is more severe and will usually continue, allowing the initial 
small cracks to grow deeper and longer. In a relatively thin (15 mils) skin, such severe crack- 
ing would result in gas and water leakage and render the insulating structure virtually useless. 
Chemical additives are often used to minimize ozone-cracking but these are usually aromatic 
amines which possess toxic characteristics. All known anti-ozonants are toxic to some degree. 
However, it is possible to prolong the life of rubber by providing a nontoxic wax coating on the 
surface which prevents ozone from attacking the rubber. Initial protection was provided by 
brush-coating the rubber parts with wax. In addition, wax was included in the liquid latex com- 
pound. Long-term protection is provided when the wax in the compound blooms to the surface. 

Finally, with regard to ozone cracking, the problem is made severe by forming curved sur- 
faces from flat laminate materials. The outer surface is always under static tension, while the 
inner surface is under static compression. The high-curvature folds on the outer surface of a 
garment so constructed are particularly susceptible to ozone attack. 

A layer of stretch nylon was added to the inner side of the insulating laminate to enhance 
the ease of donning and doffing the suit. This procedure has become rather standard in wet- 
suit construction, and it eliminates the need for talcing. The nylon lining must be fabricated 
into the laminate so that it will not cause abrasion of the diver's skin. 

To summarize the insulating- mate rial structure, starting with the inner side, against the 
diver's skin, we have a layer of stretch nylon, a thin rubber skin, a one-quarter-inch-thick 
layer of latex foam, and an outer thin rubber skin„ 

The insulating material is subject to volume changes upon changing sea-water pressure, if 
the garment is sealed to confine the gas in the foam. A decrease in ambient pressure would 
cause expansion of the gas, with a resulting stress on the laminate material. Continued expan- 
sion of the material can result in stresses of sufficient magnitude to cause delamination, a con- 
dition which would seriously alter a diver's buoyancy. The mechanics of delamination depend 
upon geometry and constraints as well as the tensile strength of the latex foam and the inter- 
laminar strengths between layers. Finished suit parts were tested for delamination pressure, 
which turned out to be nominally 3 psig differential. The limiting factor was the strength of the 
latex foam, rather than the bond between layers of material. 

Increased ambient pressure causes a decrease in volume of the insulating material. Figure 
107 shows the decrease of the open-cell latex insulating material with percent increase of ab- 
solute external pressure. Buoyancy and thermal insulation experience changes with varying 
volume. 

Relief of overpressure can be realized through use of appropriate valving in a diver's suit 
constructed of such material. Such valving was anticipated early in the program but was aban- 
doned at the suggestion of the government. The point of view was that it would not be necessary 
so long as the Sealab n aquanauts remained within the change in pressure limits which were 
physiologically safe for saturation-diving excursions. 

Insulating Gases— The thermal conductivity of an open-cell laminate depends upon the filling 
gas within the cell pores as well as the volume fractions of material and cell spaces. Various 
filling gases were considered for use during Sealab H, but the final choice, made in the field, 
was to use the habitat atmosphere having a high helium content. The criteria for selecting a 
gas to maintain the equilibrium volume of the insulating material and to enhance its thermal 
characteristics are size and weight of the stored compressed gas, its thermal properties, and, 
in the event the suit is worn in a submersible chamber, the physiological effects of the gas in 
an elevated pressure environment. Table 32 lists the thermal-conductivity values of various 
gases. 



WET SUITS 



279 




PER CENT ABSOLUTE AMBIENT PRESSURE 
INCREASE /P^Po\ X ,00 ^ 



Fig. 107. Insulation thickness of open- 
cell Laytex vs external pressure 



Table 32 

THERMAL CONDUCTIVITY k OF GASES 

[cal / (sec-cm-) (°C/cm)] 

(Approximate Values at Ordinary 

Temperatures and 1 ATM A) 



Gas 


kx 10^ 


(k,.sA.i.) 


Air (0°C) 


5.68 


1. 


Carbon Dioxide (0°C) 


3.07 


0.540 


Helium (0°C) 


33.9 


5.97 


Hydrogen (0°C) 


32.7 


5.76 


Nitrogen (7°-8°C) 


5.24 


0.922 


Oxygen (7°-8°C) 


5.63 


0.990 



Carbon dioxide is a likely candidate from the point of view of bulk and weight since, under 
adequate pressure, it can be stored in the liquid phase. The thermal conductivity of CO 2 is ap- 
proximately one-tenth that of helium. Small amounts of CO2 are readily scrubbed from the at- 
mosphere by chemical absorbents, permitting use of the gas in a life-support enclosure. (CO 2 
was selected as the insulating gas prior to the Sealab II evaluations, and a filling manifold was 
provided for filling two suits simultaneously. But the cramped space in the Sealab 11 diving 
locker would not permit use of the CO 2 filling manifold. The Sealab E habitat atmosphere was 
used rather than CO2.) 

Another interesting candidate for an insulating gas is the family of fluoromethane refrig- 
erants (DuPont's Freons), some of which are nontoxic in small concentrations. Although these 
gases are good insulators, they cannot be scrubbed from a closed high-pressure breathing en- 
vironment and would accumulate as the gas diffused from the garments. The properties of the 
Freon gases suitable for the heated-suit application are shown in Table 33. Freon-13Bl is the 
best choice, comparing all of its properties with the other Freons. Its thermal conductivity is 
only 64 percent that of carbon dioxide. Aside from their thermal characteristics, Freons are 



280 



WET SUITS 



low in toxicity, are not flammable or explosive, and do not conduct electricity. The Freons 
listed in Table 33 cause less than 1 percent elongation of natural rubber due to swelling. 

Table 33 
PROPERTIES OF FREON GASES [8] 





Thermal Conductivity, k 




Boiling 


Swelling of Natural 


Underwriters' 


Product 


[Btu/(hr. ft2)(°F/ft)] 


k A . 


Point 


Rubber (% Increase 


Laboratories 




at 32°Fk -. 10 




(°F.) 


in Length at R.T.) 


Classification 


Freon-13 


6.33 


0.445 


-114.6 


1 


6* 


Freon-13Bl 


4.9 


0.345 


-72.0 


1 


6 


Freon-115 


6.33 


0.445 


-37.7 





6 


Freon-C318 


6.27 


0.442 


21.5 





6 



*Group 6, Underwriters' Laboratories Classification of Comparative Life Hazard of Gases and 
Vapors: "Gases or vapors which in concentrations up to at least about 20 percent by volume 
for durations of exposure of the order of 2 hours do not appear to produce injury." 

Nitrogen was also considered, because it has better thermal insulating properties than 
helium and, in small percentages, can be present in a high-pressure breathing gas with no del- 
eterious effects. But it is not as insulative as either CO 2 or Freon gas. Compressed air was 
ruled out because it will support combustion and would represent a fire hazard in an electri- 
cally heated suit. 

Purging the helium-oxygen mixture from the suits with insulating gases was ruled out in 
the Sealab n habitat. This procedure was considered unacceptable because of the need for 
stringent atmosphere control. 

Thermal conductivity is not the only aspect to consider for selection of an insulating gas. 
Heat transfer by convection is also a participant in the total heat transfer across the insulating 
sandwich. Radiation will be small because of the relatively low absolute temperature differen- 
tial. No attempt was made to calculate the effect of convective cooling or to measure the total 
heat transfer coefficient of the insulating sandwich. Such study would not fit into the time 
frame of the research program. 

The effect of convective cooling in cellular materials is currently a topic of study at the 
U.S. Army Research Institute of Environmental Medicine at Natick, Massachusetts. 

Low Compressibility Insulation— Materials other than open-cell foams were evaluated for 
the insulating laminate. The use of microballoons was rigorously examined but was found to be 
impractical. The writer suggested incorporating microballoons into a diving-suit insulating 
material during 1963. Subsequent in-house research was conducted by U.S. Rubber Company to 
study the thermal and mechanical characteristics of microballoons encapsulated in a polymeric 
matrix. The matrix material was chosen to be a polyvinyl chloride plastisol for convenience. 
Its specific heat is very nearly the same as other rubber-like organic materials. 

The results of the thermal- conductivity measurements were not very promising, and the 
material was deemed too rigid for use in diver's suits. But, while there are not written reports 
offering data, there was a claim by an overseas investigator that such materials exhibit a frac- 
tion of the thermal conductivity of closed-cell neoprene at depth. The details of the foreign 
measurements were not made known, but much interest was generated in the United States. 

To settle the question, a second set of measurements was made by U.S. Rubber independent 
of the first ones. The results were not vastly different, although the sample preparations and 
measurements were performed by different investigators in independent studies. The results 
are given in Table 34. The difference between the two control samples amounts to 9.5 percent. 
This difference is probably due to different degrees of cure, degassing of the material, and 
measuring procedures. 



WET SUITS 



281 



Table 34 
MICROBALLOON/PVC PLASTISOL THERMAL CHARACTERISTICS 



Sample 


Percent 

Microballoons 

by Volume 


Percent 
Voids 


Microballoon 

Wall 

Material 


Thermal 

Conductivity 

[Btu/ (hr. ft2) 

(°F/ft.)] 


Percent 

Difference 

of 

Conductivity 


First Set 

1 (control) 

2 

3 

Second Set 

4 (control) 

5 

6 



39 
55.7* 


57.3* 
39.1 



35 
50 


34 
34 


Borosilicate 
Silica 

Epoxy 
Silica 


0.084 
0.084 
0.090 

0.092 
0.079 
0.081 


1 

+7.1 

, 
-14 
-12 


'9.5 



*The volume of closely packed uniform spheres in space is 53 percent. The 
volume of closely packed microballoons in space is approximately 69 percent. 

Microballoons were first considered because, in the loosely packed condition and without a 
binder material, the thermal conductivity is close to that of cellular neoprene used for standard 
wet suits (Tables 35 and 36). This information is given in the manufacturer's specifications 
and thermal-conductivity measurements were not made during this program to verify the manu- 
facturer's data. 



Table 35 
MICROBALLOON PROPERTIES [9] 



Parameter 


Silica 


Boro-silicate 
Glass 


Epoxy 


Particle Diameter 


30-125 microns 


30-300 microns 


0.13-0.18 in. 


Wall Thickness 


~ 2 microns 


~ 2 microns 


0.01 in. 


Bulk Density 
(Ib/ft^) 


11 


14 


15.6 


Average True Particle 
Density (gm/cm^) 


0.28 


0.42 


0.45 


Thermal Conductivity 
of Loosely Packed 
Material (Btu/hr/ 
ftV°F/ft) 


0.03 


0.04 





An analysis of the heat transfer across such a composite material indicates that thermal 
short-circuiting occurs across the elastomeric material used as the binder and across the 
glass microballoon walls. The microballoon wall materials exhibit about eight times the ther- 
mal conductivity of PVC, which tends to offset insulation due to the voids within the micro- 
balloons. See table 36 for comparisons of the thermal conductivities of materials. 

To make matters worse, the composite microballoon/elastomer material is very stiff com- 
pared to the same thickness of the elastomer alone. The high bending and elongation stiffness 
of the material makes it a poor choice for a flexible diver's suit. There is also a decrease in 
tensile and elongation strength (Table 37). 



282 



WET SUITS 



Table 36 

THERMAL CONDUCTIVITY OF VARIOUS MATERIALS [10] 

(Range of Typical Values Near Room Temperature) 



Material 


Thermal Conductivity 
k(Btu/hr/ftV°F/ft) 


Low 


High 


Pure water (12) 
Neoprene (unicellular) 
Natural Rubber Foam 
Neoprene Rubber 
Natural Rubber 
Butyl Rubber 
Polyvinyl Chloride 
Epoxies (cast) 
Silica Glass 
Borosilicate Glass 


0.348* 
0.021 

0.07 
0.1 


0.029 

0.025 

0.11 

0.08 

0.05 

0.10 

0.8 

0.8 

0.7 



♦ Somewhat lower for sea water depending on pressure, 
temperature, and salinity. 

Table 37 

BREAK CHARACTERISTICS OF MICROBALLOON/ 

PVC PLASTISOL SAMPLES 



Sample No. 


Tensile Stress 
at Break (psi) 


Elongation at 
Break (percent) 


1 (control) 

2 

3 


350 

180 

91 


330 
245 
265 



Self- Contained Power Source 

The choice of heat-release materials (resistance wires, carbon yarn, liquids, etc.) would 
have to be made after selection of the portable power pack for use by the free- swimming aqua- 
naut. Overall power efficiency was the principal criterion, because of the rather high heat 
level required and the long exposure period (three hours). 

Radio-isotopes, thermochemical reactions, fuel cells, and thermoelectric heating were 
ruled out on the basis of nonavailability of off-the-shelf components which could be integrated 
into a suit system. Secondary cells were considered because of their availability and the need 
for only minor modifications to adapt them for the application. 

A simple formula was derived to determine the size and apparent weight in water of sec- 
ondary batteries providing one kilowatt-hour of stored energy. The apparent weight is: 



W. 



(W, 



,) 



where 



Wj, is the dry weight of the battery, lb 

Vb is the volume of the battery, in.^ 

P^ is the weight density of sea water, 0.037 lb/in. ^ [11] 



WET SUITS 



283 



W. and V, are determined from: 

b b 



W,, = K/a^^^ and V^ = K/a , 



where 



K is the stored energy, watt-hours 
a^_ is the watt-hours stored per pound of battery 
a is the watt-hours stored per cubic inch of battery 
Finally, the apparent weight is: 



W = K 



75 a 



Table 38 shows the calculated weight and bulk of various battery candidates. The figures 
for weight and bulk are conservative (on the low side) and are based on nominal characteristics. 
The calculations are for the batteries alone and do not include the weight and volume of other 
components of the power pack. 

Table 38 
CALCULATED WEIGHT AND BULK OF ONE KILOWATT-HOUR BATTERIES* 



Type of Battery 


a 

w 


a 

V 


Wb 
(lb) 


Vb 
(in. 3) 


W^t 
(lb) 


watt-hr 
lb 


watt-hr 
in. 3 


Silver Zinc (secondary) 

Silver Cadmium 

Lead Acid 

Nickel Cadmium 

Silver Chloride/Magnesiumt 


55 
35 
20 
13 
30 


3.5 
2.8 
2.1 
0.9 
2.5 


18.0 
28.6 
50.0 
77.0 
33.3 


286 
358 
476 
1110 
400 


7.4 
15.4 
32.4 
35.9 
18.5 



* a^^ and a^ from Reference [12]. 

tPrimary (not rechargeable) sea-water activated. 

tWa = weight in water (apparent). 



Lead acid, nickel cadmium, Leclanche, and sea-water batteries were ruled out because of 
the bulk and weight required for storage of one kilowatt-hour of energy. Silver cadmium cells 
were just a little too large and heavy for the purpose. 

Silver-zinc, the most efficient of the secondary cells for energy storage per unit weight 
and per unit volume, were selected for the application. Thus, the portable power pack would 
provide chemically stored energy which would be released as electrical power. This suggested 
that the most efficient means of using the stored power would be direct conversion to heat 
through use of resistance wires. 

In a sense, selecting immersible silver-zinc cells opened Pandora's box because of the 
need for rather demanding maintenance and charging procedures. Off-the-shelf silver-zinc 
cells cannot be immersed in seawater without design adaptations for pressure equalization and 
waterproofing to prevent electrical shorting. 

Pressure-compensation of the individual cells can be provided by filling the cells almost 
completely with electrolyte (potassium hydroxide, 40 percent aqueous solution) and installing a 
deformable rubber bladder. Total filling is not possible for three reasons; gases are occluded 
in the plates, hydrogen is generated in the cells, and it is difficult to purge the gas bubble en- 
trapped at the top of the cell without spilling the caustic electrolyte. An alternative to pressure 
compensation would be to insert the cells into a single pressure housing, but this would increase 
the weight of the battery pack, and the weight of the cells alone is almost to the acceptable 



284 



WET SUITS 



limit. The sealed battery also presents an explosion hazard should a hot short occur within the 
cell. However, hot shorts can be predicted through proper maintenance procedures. The 
pressure-housing approach was ruled out mainly because the apparent weight concentrated on 
the swimmer's back could render him hydro statically unstable. Also ruled out was the approach 
of filling the upper part of the individual cells with insulating oil, because the oil would find its 
way between the plates whenever the diver inverted himself. 

The design of the silver-zinc cells will be discussed in the section of this chapter titled 
"Battery Pack and Power Control." 

Heat-Release Material 

Heat- release material research was oriented toward those materials which derive power 
electrically. The principal candidates were metallic resistance wires, carbon yarn and cloth, 
and electrically conducting rubber. Despite some disadvantages, resistance wires were se- 
lected as the near-future solution. All heat-release materials investigated will be discussed. 

The main factors to consider in selection of heat- release materials for a diver's suit are 
as follows: flexibility of the material configuration to maintain mobility of the diver, preven- 
tion of hot-spotting and shock hazards, compatibility with the insulating materials, appropriate 
power distribution at relatively low voltage, adequate fatigue resistance, minimal fabrication 
effort, availability of materials, constancy of heat release with static pressure, and ease of 
attaching feed wires and underwater electrical connectors. 

Heat Power Requirements— The maximum power level required of the heating system is 
about 350 watts. This level is based on experimental data obtained on NMRI subjects sitting 
motionless in a wet pot while wearing 1/4-in. -thick unicellular neoprene wet suits in 40° F 
water. The distribution of the total power is given in Table 39 [13]. 



Table 39 
HEAT POWER DISTRIBUTION 





Power 


Total 


Body Region 


Distributed 


Power 




(watts) 


(watts) 


Head 


25 


25 


Arms 


15 each 


30 


Chest 


30 


30 


Upper Back 


30 


30 


Abdomen 


30 


30 


Lower Back 


25 


25 


Legs 


20 each 


40 


Hands 


30 each 


60 


Feet 


40 each 


80 
350 



The data in Table 39 are based on subjects breathing compressed air; there were no data 
available on subjects breathing helium-oxygen mixtures. 

An average man with a skin surface area of 1.8 square meters was considered for the cal- 
culations of heat release per unit area. The body-region areas [14] were corrected to allow 
for the hood opening of the suit and for heating the hands and feet from the dorsal sides only. 
Beckman found that dorsal heating to the hands and feet is adequate and that subjects could not 
tell whether their extremities were heated from one side only or from all sides. The results 
are given in Table 40. The resistance required for each body area is also given based on a 
12-volt supply, with the various body-region heaters connected in parallel. 

Electrically Conducting Rubber— Electrically conducting rubber was studied as a possible 
heat-release material. Resistivity of electrically conducting rubbers is a fvmction of carbon 



WET SUITS 



285 



black concentration, temperature, extension, compression, and the Theological history of the 
material. Flexing of such material can damage the interfacial bonding of the carbon black par- 
ticles, resulting in irreversible resistivity changes. Decreases in resistivity with static com- 
pressional loading would cause hot regions. The negative temperature effect on resistivity 
would result in less power release whenever the rubber is allowed to cool. All of the afore- 
mentioned effects could very easily cause power- release variations in excess of the 10-percent 
maximum power variation requirement. 

Table 40 
HEAT-RELEASE-SYSTEM REQUIREMENTS 





Resistance 


Power 


Area 


Power/Area 


Body Region 


(ohms) 


(watts) 


(in. 2) 


(watts/in.^) 
10' 


Head 


5.75 


25 


282 


8.87 


Arms (each) 


9.60 


15 


140 


10.71 


Chest 


4.80 


30 


264 


11.36 


Upper Back 


4.80 


30 


357 


8.40 


Abdomen 


4.80 


30 


186 


16.13 


Lower Back 


5.75 


25 


279 


8.96 


Legs (each) 


7.20 


20 


411 


4.87 


Hand (each) 


4.80 


30 


54 


55.6 


Foot (each) 


3.60 


40 


93 


43.0 


All circuits 


0.412 


350 







Electrically conducting rubber was eliminated as a candidate heat-release material be- 
cause the resistivity cannot be controlled to the degree required in this application. 

Carbon and Graphite Yarns and Fabrics— The relatively new development of carbon and 
graphite yarns and fabrics presents interesting possibilities for diver's suit heat- release ma- 
terial. These materials are flexible and strong, have good dimensional stability, and allow 
more uniform heat release compared to resistance wires. The use of such materials had to be 
ruled out during the present program because of technological problems associated with pro- 
viding high stretch, constant resistivity, and ease of fabrication into the insulating material. 

Carbon filaments comprising carbon yarns possess a high modulus of elasticity (about 
6 X 10^ psi) along with a low elongation at break (about 3.5 percent) and a high tensile strength 
(about 1.8 X 10 ' psi). Carbon yarns are available in a range of filaments per ply, plies per 
yarn, and twists. The yarns can be woven or knitted in various configurations with or without 
other materials such as glass. Yarn and plain woven fabrics are very flexible in bending but 
very stiff in elongation. 

Knitted fabrics display some stretch, however isotropic, but suffer from filament fatigue 
due to interfilament abrasion. 

Resistance Wires— Metal alloy resistance wires remained the only candidate for immediate 
application. Despite their susceptibility to fatigue, copper alloys can be soft-soldered with rel- 
ative ease. The criteria for selection of the alloy, wire gauge, physical configuration, and 
electrical circuitry are described in the section of this chapter titled "Resistance Wire 
Circuitry." 



DESIGN 

Wet Suit and Snag Suit 

The rubber wet suit design consists of a jacket with an attached hood, trousers, mitts, and 
boots. Figures 108 and 109 show a suit on aquanaut W. Tolbert, USNMDL. General design 
features include a jacket opening from the breastbone downward, gussets on the wrists, ankles, 



286 



WET SUITS 



mitts, and boots, and the exclusive use of Velcro rather than zippers. The inner surfaces are 
lined with nylon for ease of donning and doffing. The trousers are provided with a high-rise 
back to minimize cold-water flooding in that region. The boots are fitted with high-modulus 
rubber soles to protect them against puncture and scuffing and to minimize the possibility of 
the diver slipping while walking on a wet deck. 




-SUIT PARTLY DONNED 
(a) 



COMPLETE WITH BATTERY PACK 
(b) 



Fig. 108. Aquanaut Tolbert wearing the elec- 
trically heated wet suit (a) With snagsuit 
partially donned (b) Complete with battery 
pack 




HEATED BOOT 
(0) 



NOTE ELECTRICAL CONNECTORS 
(b) 



HEATED MITT 
(c) 



Fig. 109. Several views of the electrically heated wet suit (a) The 
heated boot (b) The electrical connectors (c) The heated mitt 



The buoyancy and thermal insulation of the gas-inflated wet suit would suffer serious con- 
sequences if the outer rubber skin were punctured or torn. An outer suit, a snag suit, was 
designed to guard against tear, puncture, scuff, and abrasion. The snag-suit design includes 
using both a nonstretch and a stretch material in a zippered coverall with separate boots and 
mitts. The nonstretch material is polyurethane-coated nylon fabric chosen for strength and 
good resistance to mechanical damage. The stretch material is used to permit mobility in a 



WET SUITS 



287 



fairly snugly fitting outer garment. Figure 104 shows aquanaut Bill Tolbert with the snag suit 
partially on and with it completely on. A single front zipper and double back zippers allow the 
diver to insert his arms into the snag suit with ease. Lemon yellow coated nylon and white 
stretch fabric were chosen to enhance underwater visibility. 

The mitts are removable under water to permit maximum finger dexterity for fine work. 
They are replaced before the hand becomes painfully cold. At about 52 °F, aquanauts found that 
they could remove their mitts for about a half minute, replace them for one quarter minute and 
repeat the cycle. Figure 110 shows QMC R. Barth practicing the procedure in a training tank. 




Fig. 110. Aquanaut Barth adjusts 
the cabel -powered ac control on 
the electrically heated wet suit 
during a swimming-pool test 



Resistance-Wire Circuitry 

The following factors were considered in the design of the resistance-wire circuitry: 

1. Maximum allowable separation to prevent hot-spots 

2. Flexibility of the wire configuration for maximum mobility 

3. Power distribution required of different body areas 

4. Wire diameter and specific resistivity of the wire material. 

The best available information about hot-spotting indicated a maximum allowable wire sep- 
aration of about 3/8 in. The requirement for flexibility suggested that a sinusoidal or modified 
sawtooth pattern would be appropriate. The power distribution to the various body areas was 
shown in Table 39. Wire diameters in the range of B&S gauges 30 to 33 (0.010 to 0.007 in.) 



288 WET SUITS 

were considered within a reasonable range to obtain good configuration flexibility, adequate 
strength, and minimal bulkiness when incorporated into the laminated insulating material. 

The resistance required for a body-region circuit is determined by the supply voltage, the 
wire length, and the power required for heating the area. The resistances for body-region 
circuits were given in Table 40. The resistance-wire circuit design includes parallel heating 
wires in each area and the area circuits connected together in parallel. Single resistance 
wires for some body areas would require, within a reasonable range of wire gages, a lower 
resistivity than found in any commercially available alloy. 

A general approach was taken for the design of all body- region circuits, with the exception 
of the hands and feet, which were treated specially. The generalized configuration was designed 
as follows. 

1. Assume a configuration which is periodic, will permit stretch, and has a wire separa- 
tion, X. Let X be the wavelength of the periodicity. Then: 

lA = CjXandA/x = C^x^ 

where Cj and C2 are constants depending on the configuration, L is the wire length, and A is 
the area to be heated. We then have that: 

L/A = Cix/Cjx^ = C/x where C = Cj/Cj. 

Rewriting, we have L = CA/x, which is the wire length to cover the area in the chosen 
configuration. 

2. The supply voltage is applied across parallel heating circuits. The resistance for each 
body area circuit is: R = E-/P, where E is the supply voltage and P is the power. 

3. The resistivity of the wire is given by (R/L) j = R/L if the circuit consists of only one 
heater wire. For parallel wires of the same material emitting equal heat power, we have that: 

(R/L)i = n2(R/L)i 

arising from 

1/Ri = i;(l/Ri) = n/Ri and L = nL; 
i = i 
where the subscript, i, denotes an individual heater wire. 

4. Writing the expression for resistivity, we have: 

(R/L)j = p- 
where j denotes specific diameter and material. 

5. Introducing a requirement for an allowable power deviation, R ± e = E Vp ± € , which 
can also be written as: 

[n2(R/L)i - pJ/[n2(R/L)i] ^e . 

6. Compute the values of the expression given in step 5 for n = 1 to 20 (number of parallel 
heaters). 

7. Choose the value of n which satisfies the permissible deviation, E. 

8. If no value of n satisfies the permissible deviation, alter the configuration and/or spac- 
ing by using the value of n corresponding to the minimum e . The new spacing constant is 
given as 

x' = CjA/n^R. 



WET SUITS 



289 



9. Compute a new L for each x'. 

10. Print-out n, e , x', L'. 

This procedure was programmed on a Burroughs ElOl computer to reduce the computation 
time from several days to about a half hour. Preliminary computations indicated that alloys 
having higher specific resistivities than copper would have to be employed. Stranded wire in 
small diameters and special alloys is not commercially available. Therefore, it became prac- 
tical to attempt to use only one type of wire throughout the suit. The selection was "Advance" 
wire which, in B&S gage 33 (7 strands of B&S gate 42), has a resistivity of 0.486 ohm per inch. 
"Advance" wire alloy consists of 43 percent nickel and 57 percent copper. It has a nominal 
specific resistance of 294 ohms per circular mil-foot at 68° F and a specific heat very close to 
that of copper. "Advance" was chosen over the nickel-chromium-iron alloys because it can be 
soft- soldered with as much ease as copper. 

Table 41 shows the print-out design information corresponding to the general configurations 
shown in Fig. 111. Departures from the configuration were made near seams and gussets. 

Table 41 

RESISTANCE WIRE CIRCUITRY 

( p= 0.486 ohms/inch, x' = 0.375 in.) 





No. of 








Parallel 


Power 


Wire Length 


Body Region 


Heater 


Deviation 


(per element) 




Wires 
n 


(%) 


L' (in.) 


Head 


8 


6.0 


94.81 


Arm 


4 


4.7 


79.01 


Chest 


8 


1.3 


79.01 


Upper Back 


9 


5.5 


88.89 


Lower Back 


8 


7.0 


94.81 


Abdomen 


7 


2.8 


69.14 


Hand 1 „ 

Foot J Special cases 










Fig. 111. Electrically heated wet 
suit — general resistance wire con- 
figuration 



290 WET SUITS 

Boot and mitt circuitry were handled as specific cases. The wire configurations differ 
from those shown in Fig. 111. The mitt circuit design provides heat to the dorsal side of the 
thumb and hand and to the ventral side of the fingers. The boot circuit provides heat to the en- 
tire foot area. 

The need to interconnect the various suit parts required the use of safe underwater elec- 
trical connectors. Aside from watertight integrity, the requirements of the connectors are to 
take the current to have low contact resistance, and to be as small as possible. The current 
requirements are 3.5 amperes for the mitts and boots connectors and 15 amperes for the jacket 
and trouser connections. The mitt and boot circuits were designed to be supplied independently 
of the remainder of the suit. Electro-Oceanics connectors were employed, principally because 
of their small size and flatness. The connectors were fastened to the suit parts through neo- 
prene oral inflation tube fittings. 

Feeder wires to supply the resistance wires were chosen to be B&S gage 22 or 24 copper, 
depending on the length of the feed wire. It is important that the resistivity of the feed wire be 
very small compared to the resistivity of the heater wires, to prevent large voltage drops 
across the heating circuit. Such voltage drops result in uneven heat release. 

Battery Pack and Power Control 

The battery-pack design includes eight silver-zinc cells in fabric pouches, interconnecting 
cell cables, a battery cable assembly attached to a power-control box, and a 2-in. nylon belt 
with a fixed buckle, rather than a quick- release type. 

The silver-zinc cells are Yardney LR 85 cells modified for this application. The 12-volt 
supply consists of two banks of cells, four cells per bank, in series. The cell banks are paral- 
lel switched to provide one-quarter heat power to the suit. The cells were designed so that 
they could be immersed without using an external pressure housing. They are inserted into 
fabric pouches made of heavy-gear diver's dress material. 

The modification of the LR 85' s consists of use of watertight electrical connectors and 
total filling with electrolyte. Electro-Oceanics 51E1F female connectors were attached to the 
cell terminals and potted in place with an epoxy compound. Figure 112 shows one of the cells. 
Compressibility of the cell is minimized by nearly total fillings of the cell with the potassium 
hydroxide electrolyte. Volume changes due to gases remaining in the cell after filling, and 
gases generated by the cell during discharge, are compensated for through use of a deformable 
rubber finger. Figure 113 shows the pressure-compensating mechanism. 

The interconnecting cell cables consist of two Electro-Oceanics 51E1M male connectors 
molded onto 11 in. of B&S gage 16 wire. A battery-cable assembly, specially designed and con- 
structed for the purpose, is electrically connected to the ends of both cell banks. The cable 
terminates in an Electro-Oceanics 4104 feed-through fitting mounted on a power control box. 

The electrical circuit for the battery-pack control box is shown schematically in Fig. 114. 
The switching arrangement provides five options; no power, full power to all parts of the suit, 
one-quarter power to all parts of the suit, full power to the hands and feet only, and one-quarter 
power to the hands and feet only. It was felt that such options would be required to cover the 
range of body-heat production during various levels of work. 

The list of components shown in Fig. 114 is given below. 

Bj-Bg Yardney LR-85 modified silver-zinc cells 

C,-C,, Electro-Oceanics 51E1F female connectors 

1 Id 

Cj7 -C32 Electro-Oceanics 51E1M male connectors 
C33 Electro-Oceanics 4104 feed-through fitting 



WET SUITS 



291 



C34 


-C37 


C38 


-C41 


Si 




S2 




Fi 




F2 





Electro-Oceanic s 59 F2F female bulkhead connectors with51F2M male connectors 

Electro-Oceanics 51F2F female connectors mated to Electro-Oceanics 51F2M 
male connectors 

DPDT neutral center off toggle switch 

SPST toggle switch 

20 amp fuse 

15 amp fuse 




Fig. IIZ. Silver-zinc cell used 
to power electrically heated wet 
suit 



AC Umbilical Cable and Power Control 

The ac umbilical power cables and control boxes were designed to permit heating power 
to be derived from a source within Sealab H. The design of the cable included consideration of 
the desired cable length, the total resistance of the heating circuitry, and the voltage of the 
power source. The power source voltage was chosen as 24 volts by the contractor through con- 
sultation with NMRI and the U.S. Navy Mine Defense Laboratory. This choice determined that 
the voltage drop in the cable at full suit power would be 12 volts and that the cable resistance 
would equal the resistance of the suit circuit. The selection of cable wire gage followed. 

The ac power-cable design consists of 100 ft of two-conductor No. 12 AWG cable spliced 
to 18.5 ft of two-conductor No. 14 AWG cable. The inboard connector selected was a Cannon 



292 



WET SUITS 



straight plug with a strain relief. The wet end of the cable was terminated in an Electro- 
Oceanics 51E4F connector, with pins 1 and 2 paralleled and pins 3 and 4 paralleled. The total 
resistance of the cable assembly was chosen to be 0.412 ohm to coincide with that of the suit. 



„ _^^^2 "0" RINGS 

OZZIIZD^*-^;- AN-8 



NYLON 
FITTINQ 



OI 



"O'RINfl 
-'-''» AN-IO 



^i 



RUBBER 
BULB 



L_V^ 



T 

16 

_1 



\y 



Ky 



Fig. 113. Electrically heated wet suit pressure- 
compensating mechanism 



BATTERY PACK 



HEATED SUIT 




Fig. 114. Schematic diagram of electrically heated wet suit battery 
pack control circuit 



WET SUITS 



293 



The ac power-control box is identical in design to the battery-pack control box, with the 
exception of the power-input connector. The power cable plugs into an Electro-Oceanics 
51E4M bulkhead connector. Figure 115 shows the circuit schematic of the ac power-control 
box. The power options with the ac control are different from those in the battery-pack con- 
trol. This difference arises from series-parallel switching the suit-circuit resistances rather 
than the supply voltage. The cable resistance is an integral part of the circuit. The method of 
switching suit-circuit resistances is shown in the schematic in Fig. 115. 




HEATED SUIT 



CONTROL BOX 



Fig. 115. Schematic diagram of electrically 
heated v/et suit ac power control circuit 



The list of components shown in Fig. 115 is given below. 
CB Circuit breaker 

T J 0-125 vac variac 

T 2 115V/24 V transformer, 50 amps 

0-50 VAC voltmeter 

0-50 AMP ammeter 

30 a, 32 V fuses 

Cannon MS3102R-16-11S receptacle 

Cannon Ms3106R-16-llP plug/CA45161 strain relief 



M, 



M, 



F F 

1 ' 2 



294 



WET SUITS 



Ci 

c. 



Ca-Cf 



C7-C1 

F3 
Si 

s. 



Umbilical cable, 100 ft 2-wire No. 12 AWG plus 18.5 ft 2-wire No. 14 AWG 

Electro-Oceanics 51E4F connector, female 

Electro-Oceanics 51E4M bulkhead connector, male 

Electro-Oceanics 59F2F bulkhead connector, mated with Electro-Oceanics 
51F2M male connectors 

Electro-Oceanics 51F2F female connectors mated with Electro-Oceanics 
51F2M male connectors. 

30A fuse 

DPDT neutral center off toggle switch 

DPST toggle switch 



Other designs for power controls were considered, but the one described above was chosen 
primarily for expediency. An SCR (silicon controlled rectifier) circuit was considered, but time 
did not permit a circuit to be designed and developed which would carry 30 amperes at 12 volts 
while providing continuously variable power. 

The general power-control box design, applicable both to the battery and ac power-control 
boxes, is shown in Fig. 116. An ac power-control box is shown, but the dc box is identical ex- 
cept for the electrical input connector. 




Fig. 116. Electrically heated suit power con- 
trolbox, ac power. The upper switch controls 
power level; the lower switch selects heat to 
hands and feet or to the full suit. 



WET SUITS 



295 



DEVELOPMENT AND FABRICATION 

First Wet-Suit Model 

An unhealed pressure-compensated wet suit was constructed initially to check the suit de- 
sign and fit. This suit was tailor-made to fit CAPT E. L. Beckman and was tested at NMRI. 
Some design changes were indicated. Most of the changes were minor and do not deserve dis- 
cussion. The most important change was to add the nylon inner lining for ease of donning and 
doffing. 

The evaluation of the first suit model was generally favorable. The insulating material was 
said to feel considerably softer to the skin than unicellular neoprene. The suit enabled CAPT 
Beckman to have good mobility in the water. Mobility was not as good in air as it was in the 
water. 



The first wet-suit model was tested to observe the delamination pressure, 
were as shown in Table 42. 



The results 



Table 42 
DELAMINATION PRESSURES OF 
FIRST WET-SUIT MODEL 



Suit Part 


Delamination 

Pressure 

(psig) 


Right mitt 
Left mitt 
Jacket 
Trousers 
Right boot 
Left boot 


5 

2-1/2 

7 

4 

3-1/2 

3-1/2 



Mark I, Mod. Suit 

The second prototype evaluated was electrically heated as well as pressure compensated. 
The first snag- suit model was evaluated along with this wet suit at NMRI. Pattern alterations 
were required because of a tighter fit than the first suit around the arms and legs. This tight- 
ness was due to the increased modulus of elongation caused by the resistance wires, which were 
not present in the first suit. Other fit and styling alterations were minor. The heat distribu- 
tion in the mitt had to be redesigned because the original design provided too much heat in the 
thumb. Originally, 7-1/2 watts were applied to the thumb. This was changed to 3-3/4 watts. 
It was decided to color-code the electrical leads from the suit to the switch box. The revised 
version of the second wet-suit model became the Mark I, Mod. I suit. 

Time did not permit further suit development. Most important, it did not permit extensive 
laboratory and field tests. Likewise, there was virtually no development time for the battery 
pack or the power controls. The prototypes had to be constructed from the first design without 
extensive test and evaluation. 

The Mark I, Mod. electrically heated suit was tested to destruction for delamination 
pressure at Washington, Indiana. The suit was worn by a subject and inflated with air, part by 
part, until each suit part delaminated. The results were as shown in Table 43. 



Carbon Tape Heater Attempt 

Although the decision to use resistance wires had been made, an attempt to fabricate at 
least a few mitts heated with carbon tape was made. This development was abandoned because 
of technological difficulties. A carbon-glass tape especially woven and supplied through the 



296 



WET SUITS 



good offices of Union Carbide was laminated into the insulating sandwich material and evaluated 
electrically. 

Table 43 
DE LAMINATION PRESSURES OF ELECTRICALLY HEATED PROTOTYPE 



Suit Part 


Delamination 


Description of 


Pressure (psig) 


Delamination 


Right mitt 


3-1/2 


Balloon on dorsal side of finger area 


Left mitt 


3-1/2 


Same 


Jacket 


3-1/4 


Balloon on left sleeve just below shoulder 


Trousers 


2-3/4 


Balloon on front of left knee area 


Right boot 


3-1/2 


Balloon on inside of ankle 


Left boot 


3-3/4 


Balloon on inside lower ankle area 



The resistance of an 8-in. length of the 2-3/4-in.-wide tape was 3.97 ohms prior to lami- 
nation and 9.49 ohms afterward. The change in resistance can be explained by the poor elec- 
trical contact between the carbon yarn and the copper tinsel used as the feed wires. Liquid 
latex decreases the conductivity of these junctures in an uncontrolled fashion. The change of 
resistivity with static loading was about 14 percent and 21 percent for the unlaminated tape and 
the laminated tape, respectively. The change was a decreasing resistance which would result 
in overheating in a garment. The static load was about 1.5 psi. 

It had to be concluded that such an approach would have to be delayed until some of the 
engineering problems associated with carbon heaters are solved. 

Mark I, Mod. I Prototypes 

The electrical resistance of the Mark I, Mod. I wet-suit parts was measured using a 
Wheatstone bridge. The values are given in Table 44. Variations in the resistances are due 
principally to variations in the contact resistances of the Electro-Oceanics connectors. 

Table 44 
MEASURED RESISTANCES IN OHMS OF THE SEALAB II SUIT PARTS 



Suit No. 


Jacket 


Trousers 


L. Boot 


R. Boot 


L. Mitt 


R. Mitt 


Design 


1.25 


1.52 


3.60 


3.60 


4.80 


4.80 


1 


1.535 


1.725 


3.885 


3.915 


4.965 


4.915 


2 


1.485 


1.625 


3.845 


3.895 


4.955 


4.905 


3 


1.455 


1.665 


3.835 


3.865 


4.905 


4.995 


4 


1.395 


1.625 


3.935 


3.895 


4.975 


4.935 


5 


1.515 


1.585 


3.875 


3.925 


4.945 


4.855 


6 


1.405 


1.615 


3.895 


3.885 


4.885 


4.985 


7 


1.485 


1.665 


3.955 


3.895 


4.925 


4.945 


8 


1.525 


1.705 


4.045 


3.995 


4.985 


5.255 


2A 


(Spare 


; parts) 






4.905 


4.945 


8A 


(Spare 


i parts) 


4.265 


3.815 


5.085 


4.975 


8B 


(Spare 


; parts) 




3.825 




4.955 



The suit parts were tested for air-tightness as well as electrical resistance. 

The power-control boxes were pressure tested to 650 ft of sea water. The silver-zinc cells 
were pressure tested to 150 psig. 



Eight suits were fabricated for Sealab n evaluations, based on measurements supplied by 
the government for the following personnel: 









WET 


SUITS 


Suit No. 






Name 


Rank 


1 


M. 


S. 


Carpenter 


Commander (NASA) 


2 


R. 


E. 


Sonnenburg 


Lieutenant (MC, USN) 


3 


W. 


H, 


, Eaton 


Gunner's Mate 1st Class 


4 


R. 


A. 


Barth 


Chief Quartermaster 


5 


W. 


D 


. Meeks 


Boatswain's Mate 1st Class 


6 


F. 


J. 


Johler 


Chief Engineman 


7 


L. 


E. 


Anderson 


Gunner's Mate 1st Class 


8 


E. 


L. 


Beckman 


Captain (MC, USN) 



297 



The following is the list of equipment supplied by the U.S. Rubber Company in fulfillment 
of and in excess of requirements: 

Quantity Item 

8 Electrically heated pressure-compensated wet suits 

5 Extra mitts 

3 Extra boots 
8 Snag- suits 

8 2-in. nylon belts with web buckles 

4 12-volt silver-zinc batteries (32 cells), watertight 
electrical connectors, pressure-compensated 

32 Cell pouches for silver-zinc cells 

4 Extra cell pouches 

4 12 volt dc power-control boxes with battery cable 
assemblies and cell jumpers 

4 Extra cell jumpers 

4 AC power control boxes 

4 Power cables, 118-1/2 ft long. Cannon and Electro- 
Oceanic s fittings 

25 Manuals, aquanaut Suit (Mark I, Mod. I) 

8 Zippered bags for suit storage 

8 Talc bags for dusting rubber parts 

1 Two- suit purging manifold 

1 Rubber repair kit 

1 Battery maintenance kit 

1 Fabric repair kit 

1 Power-control maintenance kit 



Silver-Zinc Cells 

The pressure-compensation fitting at the top of each silver-zinc cell had originally been 
made of stainless steel. Salt-water immersion tests indicated a leakage current of 0.4 ampere 
across eight cells (about 12 volts). Coating the steel with silicone grease or petroleum jelly 
was attempted but did not solve the problem adequately. The fittings were remade using nylon. 

The O-Ring seal around the rubber bladder was introduced after Ty-wraps failed to pro- 
vide a good seal. This seal was important, as the electrolyte (potassium hydroxide) is a strong 
caustic and is therefore hazardous. 

The cells were fabricated by the Yardney Electric Company for the U. S. Rubber Company. 



Power Controls 

Time did not permit development of the power-control boxes. They were designed and 
fabricated at the Research Center. Water leaks were experienced due to hairline cracks in the 
heliarc weldments of the aluminum parts. These were repaired by filling them with epoxy 



298 WET SUITS 

resin under vacuum. The boxes were plated with chemically deposited nickel and coated with 
epoxy paint. They were individually pressure tested to 650 ft of sea water. 

TRAINING AND FIELD ENGINEERING 

The need for training personnel in the use of the suits and ancillary equipment was con- 
sidered vital because of the novelty of the hardware. Field engineering was also considered 
important, because of the experimental nature of the newly developed suits, batteries, and 
power controls. The writer carried out this work at the Sealab II site from Aug. 24, 1965, to 
October 3, 1965, with the cooperation of CAPT E. L. Beckman (MC) USN. 

Training 

Elaborate plans for rather thorough training were shattered by the nonavailability of the 
Team 1 subjects for whom suits had been provided. LT R. E. Sonnenburg was the only Team 1 
subject who received any training at all, and that was limited to less than half a day. The others 
in Team 1 who wore the suits were CMDR M. S. Carpenter, Chief Engineman F. J. Johler, and 
GMl W. H. Eaton. These personnel were available only to try on the suits to check fit just 
prior to their descent. 

All personnel in Team 2 who wore the electrically heated suits were familiarized with the 
equipment and trained in its use fairly thoroughly. The measurements of all Sealab 11 aqua- 
nauts were studied to determine whether or not the suits could be used by personnel other than 
those for whom they were made. Substitute subjects on Team 2 were found and displayed 
eagerness to assist in the suit evaluations. They were: 

Suit No. Name Position 

5 Wo T. Jenkins Equipment Specialist/Diver 

7 W. H. Tolbert, Jr. Oceanographer/Diver 

8 G. B. Dowling Research Physicist/Diver 

These personnel are civilian researchers attached to the U.S. Navy Mine Defense Labora- 
tory at Panama City, Florida. The fourth member of Team 2 to wear the suit was Chief 
Quartermaster R. A. Barth of the same Navy organization as the civilian divers. 

The Team 2 personnel were trained at the Scripps Institution of Oceanography in large out- 
door tanks filled with ocean water. Training varied from subject to subject, but all generally 
received the same instructions and had equal opportunity to become completely familiar with 
the suits and equipment. All subjects (including LT Sonnenburg of Team 1) were specifically 
asked if they would be able to reach the bypass and pop-off valve of the Mark VI while wearing 
the electrically heated suit. The amount of lead weight required to achieve negative buoyancy 
was evaluated individually by each of the subjects. The complete battery pack weighs 35 lb in 
air and 16 lb in sea water. Both the battery pack and the umbilical cable were employed during 
training sessions. For training purposes, the umbilical power cable was supplied by two 12- 
volt lead-acid storage batteries in series. In addition to the training session at Scripps, W. H. 
Tolbert, Jr. made a dive off one of the Naval Electronics Laboratory docks using compressed- 
air scuba and the umbilical cable. 

Three members of Team 3 were also trained at Scripps. Two of them were fitted with 
suits fabricated for others. They were: 

Suit No. Name Position 

3 J. J. Lyons Engineman 1st Class 

6 R. Grigg Graduate Student - Scripps 

Institution of Oceanography 



WET SUITS 299 

The third subject was BMl W. D. Meeks. The Team 3 subject training was incomplete 
because their suits had malfunctioned to various degrees during the Team 1 and Team 2 evalu- 
ations. The suits were not worn during the Team 3-stay in Sealab 11. 

Field Engineering 

The field-engineering work was concerned mainly with charging and maintaining the silver- 
zinc batteries, maintaining the suits, familiarizing the surface staff members with the heated 
suit program, conducting liaison with the subjects on the bottom to instruct and assist them, 
and perhaps most important of all, to take care of the legion of seemingly small problems in- 
variably associated with accelerated research and development programs. 

The first problem encountered in the field was poor fit of the chin area in both the wet 
suits and the snag suits. This was nearly universal and occurred in all but two suits. The chin 
areas of the suits were too tight, causing both upward forces and forces directed toward the 
back of the head. The chin area is critical, both for comfort and safety. The suit parts were 
returned to the Clothing Plant, altered, and returned by air express. The value of field engineer- 
ing was demonstrated to be essential in this instance. The program might very well have ended 
here without it. 

Most of the subjects found it difficult to put their swim fins over the boots. The boots are 
slightly bulkier than standard l/4-in. neoprene boots because of the added hard sole. Dr. 
Sonnenburg found it impossible to wear his super-extra-large Duck Feet over the heated boots, 
and extremely difficult to wear them over any other boot. To solve this problem, the writer 
provided a pair of altered super-extra-large Duck Feet with 2-in. nylon webbing and buckles 
rather than the fixed rubber strap. It would be well if the fin manufacturers provided swim 
fins for size 13 and 14 feet which are covered with 1/4-in. boots. But they do not. 

Battery charging and maintenance accounted for a significant fraction of engineering time. 
Silver-zinc cells require careful attention during the charge cycle, unless automatic scanning 
chargers are employed. None were available. The cells are generally charged at constant 
current until the end-of-charge voltage is attained. They can be ruined if current is main- 
tained after the end-of-charge voltage has been reached. 

An attempt to charge the cells was made aboard the Sealab 11 staging vessel, but it was un- 
successful and had to be abandoned. Power-line surges due to heavy electrical equipment in 
the circuit together with an inadequate patch-board for connecting the cells were the principal 
obstacles. An arrangement was made to have the cells charged at the Battery Maintenance 
Shop at the Naval Electronics Laboratory at Point Loma. The cells were charged at 6 amps 
until the normal end-of-charge voltage (2.05 volts) was achieved. But these cells did not pro- 
vide power to a suit the very next morning. The voltages measured at that time were between 
1.52 volts and 1.83 volts. Most readings were about 1.58 volts. The open-ciruict readings 
should have been 1.86 volts. 

The problem turned out to be the resistance of the underwater electrical fittings, which 
was greater than the resistance of the cells. This difference in resistances resulted in voltage 
drops across the connectors had spurious voltage readings. The cells were then charged at 3 
amperes to the end-of-charge voltage. This procedure, however time consuming, was a solu- 
tion. The batteries did not deliver full capacity during the first discharge, even though they 
were partially developed by Yardney prior to shipment. They had been put through one charge- 
discharge cycle. Development of a silver-zinc cell consists of several charge-discharge cycles 
until full capacity is achieved. The high resistance of the electrical connectors caused erro- 
neous voltage readings during the development cycles, and the cells were not fully developed. 

The pressure-compensating fittings had to be removed and washed after each use. Potas- 
sium hydroxide forms a salty deposit which can be removed by vigorous washing in freshwater. 

Three of the suits worn by Team 1 members were flooded because valves were left open. 
This was attributed to the nonavailability of the subjects for indoctrination and training. The 
sea water was removed by applying a vacuum to the suit parts. Flooding of these suits vitiates, 



300 WET SUITS 

at least partially, the evaluations. Even after applying a vacuum until no further water was re- 
moved, the latex foam was found to be damp several weeks later when the suits were examined 
for malfunction analyses. The vacuum pump and a technician were supplied through the good 
offices of Professor H. Bradner, University of California. 

EVALUATIONS 

CAPT E. L. Beckman and the writer interviewed the suit evaluators to obtain their subjec- 
tive impressions. No significant numerical data were collected, e.g., skin and rectal tempera- 
tures, heat-power cycles, oxygen consumption, etc., during the dives. The evaluations were 
recorded on a portable tape recorder and subsequently transcribed. 

The general consensus of opinion among the subjects who evaluated the suits was that such 
suits, with appropriate improvements, would indeed be valuable in operational diving. Most of 
the complaints were ones that the suit-project personnel could forecast prior to the Sealab II 
evaluations. These were associated mainly with inadequate time for thorough design, develop- 
ment, and testing prior to the construction of the final prototypes. 

The suits were evaluated both by divers using both the Mark VT (semiclosed circuit breath- 
ing apparatus - 85 percent helium, 15 percent oxygen) and the Arawak hose-supplied apparatus 
(Sealab n habitat gases). 

Suit Design and Fit 

The design of the rubber suit was acceptable with minor reservations. The hood attached 
to the jacket succeeded in preventing free flooding in the neck region. The jacket opening from 
the breastbone downward eliminated pressure points on the trachea - a condition usually asso- 
ciated with neck-level front zippers and separate hoods. The Velcro closure material was 
judged to be superior to zippers in reliability. The trouser design was good in that the Velcro 
gussets at the waist and ankles made donning fairly easy. Removal of the trousers and jacket 
was difficult because the Velcro wrist and ankle gussets tended to lock together when the gar- 
ments were peeled off. The mitts were somewhat bulky and suffered from moderate flooding. 
The boots also suffered from flooding and were quite difficult to fit into swim fins. 

The electrical connectors on the boots were difficult to make and break because they were 
on the outside of the ankles. The inside of the ankle is much more accessible when a subject 
is sitting down. He merely crosses his leg. The Electro-Oceanics electrical connectors were 
very compact but required some effort to make and break. 

The snag suit was objectionable for some subjects in that it was time consuming to don and 
doff. Others had no problems. But this was mainly a problem of fitting. Nylon zippers used on 
the mitts, boots, and sleeves experienced a high mortality rate. ^^ 

Rubber-suit fit ranged from very good to poor. Most of the subjects found the chin area to 
be too tight. This almost universal problem required immediate alterations. It is difficult to 
evaluate suit fit, because suits were not always worn by personnel for whom they were made. 
CDR Carpenter experienced some tightness in the sleeves. 

Most subjects enjoyed the softer feel of the suit material compared to neoprene wet suits. 
Several aquanauts wore their heated suits for short dives without using the heat power because 
the suits were quite comfortable. One judged his suit to be superior in insulating qualities com- 
pared to neoprene suits. 

Heat Power 

Evaluations of the heat-power distribution were sometimes made by subjects who were 
busy doing other chores. Therefore, their evaluations represent recollection of comfort with 
some uncertainty. Skin-surface temperature measurements would have removed some of this 



WET SUITS 301 

uncertainty. However, several aquanauts had the opportunity of concentrating on their thermal 
comfort and gave detailed evaluations. 

The heat-power distribution was evidently close to ideal. No subject complained of signi- 
ficant unequal heating. Most subjects agreed that the power distribution was adequate. 

There was some hot-spotting in the boots and mitts, and only one man reported a hot spot 
at the lower rear part of his neck. Hot- spotting in the boots occurred in the sole area and was 
aggravated whenever the diver's weight caused pressure on his soles. This problem can be 
corrected by heating only the upper parts of the foot. Hot-spotting in the mitts occurred on the 
knuckles, where the contact pressure with the mitt is maximized by flexing the fingers. Lower- 
ing of local wire temperatures by incorporating more wire may solve this problem. 

Snug-fitting heated wet suits will require careful fitting to prevent hot areas due to the 
pressure of the suit against the skin. 

Power Source and Control 

There were no serious problems with the ac power source in Sealab n. The negatively 
buoyant electrical umbilical cable had to be pulled along the bottom whereas the positively 
buoyant Arawak hoses floated overhead. The two should have been mated together. But the 
electric cable was fed out of the Sealab n hatch, while the Arawak hose passed through a bulk- 
head. A systems approach in future programs should eliminate nuisance problems of this type. 
One subject reported that his cable became disconnected from his power-control box. A safety 
lock will prevent this from happening in the future. 

The silver-zinc battery pack was too bulky. A question exists as to whether or not it is safe 
when worn with the Mark VI. Some subjects feel that it is safe; some do not. The battery could 
have been one-third the size for Sealab 11. A one-kilowatt-hour battery to provide three hours 
of heat at full power was specified in the contract. However, the gas duration of the Mark VI 
was only about 50 minutes. 

The power-control boxes maintained watertight integrity and operated well electrically. 
The uppermost switch control (power range) was easily knocked out of position. A more posi- 
tive switching arrangement will have to be designed. 

Miscellaneous 

Only one subject reported skin irritation. All others reported none. The afflicted diver 
stated that his skin was discolored prior to donning the suit and that he wore the suit for more 
than 12 hours. His skin may have been abraded by the wet nylon suit lining. 

All subjects found it difficult to don their fins over the heated boots. It will be necessary 
to wear a larger fin over the heated boots unless the boot is made thinner. However, this would 
reduce its insulating property and require more electrical heating. Additional heating will 
mean less battery time, or larger batteries. 

On the positive side, at least three subjects wore the suits without using the supplemental 
heat power. They claimed that the suits did not suffer from the pressure effect as did their 
sponge neoprene suits. The suits achieved normal dimensions immediately after opening the 
gas valves in Sealab U. Neoprene suits, on the other hand, were severely distorted for the 
first few days, until the habitat atmosphere gases permeated the closed cells. Upon ascent to 
the surface, the neoprene suits were severely distended for several days. The pressure- 
compensated suits were decompressed instantly by opening the gas valves. 

MALFUNCTION ANALYSIS 

The principal reason for malfunction of the suits was resistance-wire fatigue and consequent 
failure. Ozone cracking of the natural rubber skin material was evident to a moderate degree. 



302 WET SUITS 

Water leakage into the insulating foam was experienced due to pin holes, tears, and human 
error. Although there was some criticism of the battery pack, umbilical cable, and power- 
control boxes, these components did not malfunction at all. The rubber suits stood up quite 
well to the rigors of repeated donning, diving, and doffing. The snag suits, although objection- 
able, experienced only zipper failures and some seam splitting.- 

The resistance wires failed in the various suits from minor to major degrees. Suit parts 
were dissected and examined for wire failure as well as ozone cracking, pin holes, tears, and 
moisture in the foam. 

Nearly all of the boots and mitts malfunctioned electrically. More wire breaks occurred 
in the "uppers" of the boots than in the soles. Wire failure in the mitts seemed less systematic. 
The boot and mitt wire design simply did not allow enough stretch, and the wires were severely 
strained. Of seven boots examined for wire breakage, there was a total of ten breaks in the 
soles and about 31 in the uppers. Five mitts were examined. Eighteen breaks occurred in the 
palm side, while 12 occurred on the dorsal side. 

Two jackets and two trousers were also examined. Wire breaks occurred mainly in or 
near areas of high suit material extension: hood, sleeve, upper back, and leg (especially the 
knee area). 

Breakage of the resistance wires was evidently followed by electrical arcing and metal 
corrosion. Arcing resulted in scorching of the foam rubber, while corrosion contributed to 
further wire failure. 

Fourteen out of 16 suit parts had moist or wet latex foam due to pin holes or tears in the 
outer skin or because gas valves were left open during sea-water immersion. Tears occurred 
in suit parts not protected by snag suits. Valves were left open only by Team 1 subjects who 
were not made available for thorough training. 

Thirteen out of 18 suit parts displayed ozone cracking to various degrees. All mitts, three 
out of eight boots, and all jackets and trousers suffered ozone cracking. 

No delamination of the insulating sandwich material was evident in any suit part examined. 
The copper "feed" wires were all intact, as were the soldered connections to the underwater 
electrical connectors. All potted solder joints were in good condition. 

The rubber suit seams were in excellent condition. None of the Velcro closure material 
suffered from any apparent wear or damage. There was only minor separation of the stretch 
nylon liner material from the inner latex sMn. 

Ozone cracking can be minimized by applying a layer of neoprene latex to the skin material 
prior to suit fabrication. Some snag and abrasion resistance without a separate snag suit can 
be realized through the addition of an outermost layer of stretch nylon. This will result in a 
stiffer suit, but it is the price one must pay for durability and speed of donning and doffing. 

The resistance-wire problem requires a complete redesign of the wire configuration as 
well as more durable wires. The stranded wires (7/42 Advance) do not have adequate flex- 
fatigue characteristics. Many more finer filaments of higher modulus alloy should be em- 
ployed. They should be coated with an insulating material which will not bind them all together. 

RECOMMENDATIONS FOR FUTURE WORK 

The principle of supplemental heating in a pressure-compensated wet suit has been demon- 
strated conclusively to be worthwhile for saturation diving. With the inclusion of a constant- 
volume feature, these suits also will be extremely useful for deep diving from the surface. It 
would seem appropriate to continue the development of such suits until they are operationally 
acceptable. 



WET SUITS 303 

Specific recommendations for a second-generation suit are outlined below. Following this 
outline, suggestions are offered for the research, design, and development of other approaches 
to thermally protective underwater garments. 

Electrically-Heated Constant- Volume Wet Suit 

Based on the evaluations of Sealab II subjects and Navy and U.S. Rubber project personnel, 
the following design alterations and additions should be incorporated into an improved suit. 

Jacket— Alter the face profile, use a soft-rubber face seal, remove bunching in the chest 
area, prevent Velcro from attaching to itself while donning and doffing. 

Trousers— Lower the hip openings, make ankle area softer to minimize chafing, prevent 
Velcro from attaching to itself while donning and doffing. 

Mitts— Extend length by about one inch. 

Boots— Use stocking seal, increase height by one inch, position gussets and connectors on 
inside ankle areas, try to make it easier to don swim fins. 

Snag Resistance— Apply stretch nylon to outer surfaces of all suit parts, supply separate 
chafing gear kit to be used as required only for severe conditions, avoid snag-suit design used 
previously. 

Resistance Wires— Redesign wire layout configuration, design new insulated wire for max- 
imum resistance to failure in flexing and kinking. 

Power Control— Provide positive switch positioning for both ac and dc operation, design 
special continuous power control silicon- controlled rectifier circuit for ac umbilical cable use. 

Voltage— Employ 24 volts to reduce current through connectors and switches and to make 
system compatible with swimmer propulsion units. 

Battery Pack— Provide capacity compatible with scuba gas-supply duration (about one hour), 
design pressure- resistant single battery housing to be suspended from scuba bottle(s), avoid 
the maintenance and charging problems encountered previously. 

AC Umbilical Cable— Provide safety lock to prevent inadvertent disconnection from power- 
control box, "marry" to Arawak hose, use bulkhead connection to Sealab HI. 

Constant Volume— Add low-pressure differential pop-off valves to rubber suit, provide in- 
sulating gas (Freon 13B-1, CO2, or Nj) bottle to be attached to scuba or to "come-home" bottle 
of Arawak, provide pressure regulator and manual flow control. 

Connectors— Design special gas/electric connectors for suit parts for minimal size and 
quick operation. 

Tailoring— Obtain accurate measurements, draft patterns, and provide fitting and alteration 
service. 

Testing— Perform thorough testing prior to use at Sealab III, incorporate modifications 
where necessary and if possible prior to Sealab m. 

Training— Conduct thorough training sessions in a tank and in open water. Subjects should 
become completely indoctrinated prior to use during saturation dives. 

Field Engineering— Provide services in the field to maximize successful usage of the suits. 



304 



WET SUITS 



Electrically Heated Undergarment 

Preliminary work has been done to develop electrically heated undergarments. U.S. Rubber 
has begun to develop techniques by which such garments can be made waterproof and stretch- 
able. A thin, high-stretch immersible garment could be worn under almost any type diver's 
suit; wet suit, dry suit, lightweight dress, standard dress, etc. Such a garment would be versa- 
tile while moderately priced. 

Water-Heated Suit 

Plastic tubing incorporated into a stretch fabric holds great promise for heated diver's 
suits. U.S. Rubber has developed a knitting technique for producing this structure. Figure 117 
shows a stretch fabric-plastic tube sample. Hot water pumped through the tubing would serve 
as the heat-release material. The advantage of this method of heat release is that it is directly 
compatible with thermochemical and isotope power sources, whereas resistance wires are not. 
Hot water also could be pumped into the suit via an insulated hose to the surface or to an under- 
water habitat. 




Fig. 117. Stretch fabric, plastic tube material 



Other 



New developments in carbon-yarn technology should be monitored, since the material has 
many merits. Materials research is necessary to provide superior insulation along with dura- 
bility, maintainability, and mobility. The development of power sources would seem important. 
Power sources more efficient than silver-zinc secondary batteries in terms of weight and 
volume would be desirable. Lastly, the problem of thermal protection for swimmers and divers 
should be considered vital enough to warrant a concentrated effort until good working solutions 
are found. 



WET SUITS 305 



REFERENCES 



1. Beckman, E. L., "A Review of Current Concepts and Practices Used to Control Body Heat 
Loss During Water Immersion," Research Report, Naval Medical Research Institute, 
Bethesda, Maryland, Sept. 12, 1964 

2. Beckman, E. L., E. Reeves, R. F. Goldman, "A Review of Current Concepts and Practices 
Applicable to the Control of Body Heat Loss During Water Immersion," Research Report, 
Naval Medical Research Institute, Bethesda, Maryland, Undated 

3. Beckman, E. L., E. Reeves, R. F. Goldman, "Current Concepts and Practices Applicable 
to the Control of Body Heat Loss in Aircrew Subjected to Water Immersion," Research 
Report, Naval Medical Research Institute, Bethesda, Maryland, Undated 

4. Provins, K. A. and R. S. J. Clarke, "The Effect of Cold on Manual Performance," J. Oc- 
cupational Medicine 2:169-175 (1960) 

5. McQueen, J. D., "Effects of Cold on the Nervous System," The Psychology of Induced 
Hypothermia, edited by R. D. Dripps. NAS-NRC Publication 451, Washington, pp. 243-60, 
1956 

6. Virtue, R. W., "Hypothermic Anesthesia," Thomas, Springfield, 111., 1955 

7. "Handbook of Chemistry and Physics," 37th Edition, Chemical Rubber Publishing Company, 
Cleveland, 1955 

8. "Freon," Dupont Technical Bulletin B-2 

9. "Eccospheres," Emerson and Cummings, Inc., Canton, Massachusetts 

10. "Materials in Design Engineering," Vol. 60, No. 5, Mid-October 1964, Reinhold Publishing 
Corporation., New York 

11. Sverdrup, H. U., M. W. Johnson, R. H. Fleming, "The Oceans," Prentice-Hall, Inc., New 
York, 1942 

12. Fried, S., "Designing With Batteries," Electronic Equipment Engineering, Jan. 1962 

13. Negotiated Solicitation 524-65Q (National Naval Medical Center), U.S.N. Purchasing Office, 
Washington, Apr. 16, 1965 

14. Burton, D. R. and L. Collier, "The Development of Water Conditioned Suits," Royal Aircraft 
Establishment Technical Note. No. Mech. Eng. 400, Ministry of Aviation, London, Apr. 
1964 



Chapter 38 
ENGINEERING EVALUATION OF SEALAB II 

'. B. Culpepper, R. B. Porter, W. P. Frost, and B. Deleman 

U.S. Navy Mine Defense Laboratory 
Panama City, Florida 



INTRODUCTION 



Project Sealab II was the second in the U.S. Navy series of tests of man's ability to live 
and work underwater at ambient pressure for extended periods of time. The underwater test 
phase began Aug. 28, 1965, and was successfully completed Oct. 10, 1965. The test site was 
approximately 3,000 ft off the Pacific coast at Scripps Institute of Oceanography at La JoUa, 
California, in 205 ft of water near Scripps Canyon. Twenty-eight men, divided into three teams, 
lived and worked for 15 days each in a synthetic atmosphere of 4 percent oxygen, 85 percent 
helium, and 11 percent nitrogen at an ambient pressure of approximately 102 pounds per square 
inch absolute (psia). 

The Sealab II craft, which served as the undersea quarters for the aquanauts, was 57-1/2 ft 
long and 12 ft in diameter, with a semielliptic head on either end. It was equipped with the nec- 
essary life-support equipment, such as breathing-gas systems, ventilating system, heating sys- 
tem, electric and communication systems, food-stowage and preparation facilities, sanitary 
facilities, and berthing and work space. 

This report presents a brief description of Sealab II and associated systems and facilities 
and their evaluation from an engineering standpoint. The evaluation is based on observation, 
interviews with the aquanauts, and recorded data. 

HULL 

General 

The hull of Sealab II was designed as an internal pressure vessel 12 ft in diameter and 
57-1/2 ft in overall length, in accordance with the 1962 ASME Boiler and Pressure Vessel 
Code, Section VIII, unfired pressure vessels. The design working pressure of 125 pounds per 
square inch gauge (psig) was selected so that the vessel could be fully pressurized on the sur- 
face and then lowered to the required working depth of 250 ft. Because of handling problems 
encountered with Sealab I, complete surface pressurization was used to minimize the time re- 
quired for lowering of Sealab II. The hull-plate material utilized was mild steel one inch thick, 
since the strength-to-weight ratio was not critical (additional ballast was required for sub- 
mergence). Some decided advantages in the use of this material for a vessel of this size are 
ease of fabrication and the avoidance of postwelding heat treatment. The hull ends were ASME 
semielliptic heads, which were explosively formed because of the long lead time involved in 
procuring commercially formed heads. For arrangements and locations of items described in 
the following sections, refer to Figs. 118 through 122. 

Ports 

Eleven circular viewing ports were installed in the hull. To avoid the restricted field of 
view through the 12 -in. ports in Sealab I, these ports were made 24 in. in diameter. Each port 
was fitted with an internal pressure-tight steel cover to protect the plastic port lights during 

306 



ENGINEERING EVALUATION 



307 




X 
o 

Tl 



ni 



308 



ENGINEERING EVALUATION 




^1 
o 



c 

M 
o 
a 






BO 

•H 

ft. 



ENGINEERING EVALUATION 



309 




T3 
U 

o 

XI 



00 

X 
o 
o 



X: 
as 



00 

•rH 



310 



ENGINEERING EVALUATION 







ao 



o 



o 



XI 
n) 

i-H 

(U 






ENGINEERING EVALUATION 



311 



CURT4IN ROD 



CURTAIN RT 



HEATER P/S 



FLG COAMING I 
FOR -|- ANCHOR 
BASES 





HEATER P/S 



Fig. 122. Sealab II section views 
of berthing area 



surface pressurizing and submersion of the vessel. These covers were fitted with vents to fa- 
cilitate equalizing the pressures on the port lights during lowering and raising operations. 
External (vented) protective covers were also provided to prevent damage to the port lights 
during handling operations. 



Access Openings 

Three access openings were provided. All hatches opened inward to reduce bolting re- 
quirements. The main access hatch was located in the hull bottom near the stern in the entry- 
way. A hatch diameter of four feet was selected for adequate clearance for swimmers with 
scuba gear. An emergency exit opening was provided in the hull bottom near the bow, in the 
berthing space. This hatch was of a standard submarine type, 30 in. in diameter. The emer- 
gency exit hatch was covered with a plywood panel to provide a deck between the tables and the 
forward berths. This hatch was intended to serve as an emergency exit in the event of any 
equipment casualty which might introduce toxic fumes into the Sealab II atmosphere. A surface 



312 ENGINEERING EVALUATION 

access hatch was installed in the top of the hull amidship. This hatch was also of a submarine 
type, 30 in. in diameter, and provided access to the Sealab II interior while in the water but 
still on the surface. 

Entry Trunk 

A trunk 8 x 8 ft by 2-1/2 ft deep was installed below the hull around the main entry hatch. 
Since the main entry hatch was to remain open at all times while Sealab Ii was inhabited, the 
entry trunk was designed to provide a displacement volume to compensate for seawater pres- 
sure variation caused by tidal action, in addition to the expected internal gas pressure fluctua- 
tions. It was determined that the predicted tidal range of nine feet would cause a 2-1/2-ft ex- 
cursion of the water level in the entry trunk. However, it was necessary to keep the gas volume 
of the entry trunli (approximately six tons displacement) small so as to reduce the tipping 
moment create by this increased buoyancy at the stern of the craft. Compensation by ballast- 
ing from the si -face was not considered feasible. 

Shark Cage 

A protective enclosure of expanded metal was built around the entry trunk. Approximately 
8 ft wide by 12 ft long, this enclosure provided a protected observation point or retreat in the 
event that sharks were in the area. A dutch door, 4 ft wide by 6 ft high, was provided to permit 
access if the lower portion of the door was embedded in the sea bottom. The lower foot of the 
shark cage was made of chain to allow conformity with a possible uneven bottom. 

Support Structure 

The support structure was designed to provide a clearance of 6-1/2 ft between the hull and 
the sea bottom. Bottom bearing plates (two each 3 ft x 18 ft) were installed to provide a maxi- 
mum seafloor bearing stress of 300 psi. On-site tests of the seafloor had indicated a minimum 
soil-bearing strength of 1300 psi. 

The use of leveling jacks was considered but was rejected because of their cost and the 
time required to provide them. Site surveys indicated a maximum bottom slope of 5 percent 
(approximately 3 degrees) and no need for such jacks. 

Spades were installed at each end of each bearing plate, so as to penetrate the bottom and 
reduce the possibility of lateral movement. 

Hull Penetrations 

All hull penetrations for gas lines, water line, sanitary drains, and cables, were located as 
near deck level as possible to minimize loss of atmosphere and flooding of Sealab II in the event 
of external line damage. These penetrations were sealed by double stuffing tubes, or the pipes 
were welded to the hull. Hull penetrations were optimally located to minimize the lengths of 
high-pressure lines inside Sealab II. A 10-in. pipe was installed through the bottom near the 
a:t'j_ end of the lab space to accommodate power leads for the outside diving lights and signal 
leads for the benthlc lab, an underwater data multiplexing and telemetering system developed 
by the Marine Physical Laboratory of the University of California. This pipe extended from 
the horizontal centerline of the hull to a point 2-1/2 ft below the hull, so that the required ca- 
bles could be installed upon removal of a pressure-tight bolted flange after habitation of Sea- 
lab II. A 3 -in. pipe was installed inside the 10-in. pipe to provide shielding between the diving 
light power leads and the benthic lab signal leads. Bilge drains with manually operated valves 
were provided to allow draining the bilges overboard while Sealab II was on bottom. 



ENGINEERING EVALUATION 313 

Variable Ballast 

The upper portion of the hull volume (3 ft deep by full hull length) was utilized for water 
ballast. This volume was divided into three separate tanks (No. 1, forward; No. 2, amidships, 
and No. 3, aft). A fourth tank was provided by the "conning tower," which also served as a 
breakwater for the surface access hatch. The internal tanks were designed to withstand a 
pressure differential of 15 psi across their flat bottoms. Internal ballast tanks were utilized 
for several reasons: 

1. To reduce internal gas volume and consequently the total volume of helium required 
for charging. 

2. To reduce the virtual mass of the entire structure in water by eliminating external 
ballast tanks. 

3. External ballast tanks would have severely limited the field of view from the Sealab II 
viewing ports towards the sea bottom. These ballast tanks were utilized to provide 

a. Adequate positive buoyancy for surface tow and systems checkout. 

b. Negative buoyancy for lowering and raising. 

c. Adequate negative buoyancy for necessary stability on bottom. A maximum negative 
buoyancy of 13 tons was required to provide bottom stability in a maximum athwartship cur- 
rent of 2 knots. 



Fixed Ballast 

Fixed ballast was provided by: 

1. Concrete inside the hull to deck level except in the entryway. 

2. Lead weights secured in the ballast tray underneath the hull. 

Lead pigs in ballast trays located fore and aft under the topside walkways were utilized to pro- 
vide final fore and aft trim. 

Hull Insulation 

The insulation used in Sealab II was Navy "standard stock" submarine corkboard in one- 
inch-thick boards. The coefficient of thermal conductivity (k) for this material at standard 
atmosphere is 0.025 Btu/hr-ft-°F. The overhead was insulated with one inch and the hull sides 
with two inches of this corkboard. No insulating material was utilized on the concrete deck 
except carpet, since radiant heating cables were installed in the concrete. The thermal con- 
ductivity (k) of helium is 0.090 Btu/hr-ft-°F, six times that of air. Since the insulating mate- 
rial was to be permeated by the helium at the ambient pressure of approximately 102 psia, the 
theoretical coefficient of thermal conductivity (k) for the cork insulation under ambient condi- 
tions was calculated to be 0.100 Btu/hr-ft-°F. This value of k was then utilized to calculate 
the expected heat losses in Sealab II, as shown in Appendix B. 

UMBILICAL CORD 

An umbilical cord provided the necessary utilities from the support vessel to Sealab n. 
The original umbilical cord consisted of five components, providing: 

1. Alternate electrical power 

2. Communication circuits 



314 ENGINEERING EVALUATION 

3. Atmosphere gas supply 

4. Atmosphere gas sampling 

5. Compressed air for pneumatic tools (external use only). 

The umbilical cord was permanently attached to Sealab II near the top of the "conning 
tower." The power and communication cables penetrated the hull through pressure -proof 
stuffing tubes. The hose components of the umbilical cord were connected to piping installed 
on the exterior of the hull with two-way shut-off, quick-disconnect type connectors. The piping 
for the atmospheric gas supply and atmospheric gas -sampling systems penetrated the hull 
through welded hull fittings. The compressed air piping terminated in four valved hose con- 
nections located on exterior corners of the hull. These connections provided for the operation 
of pneumatic tools in the sea. 

The alternate power cable was of Navy type THOF-42 (three conductor 42MCM). The 
communication cable was a neoprene -jacketed 33 -conductor TV cable, Boston Insulated Wire 
Company No. TV-33N. The short lead time allowed did not permit the design of a special 
communications cable. 

During checkout at Long Beach, California, it was found that the hose components had been 
kinked, causing the hose liners to separate from their jackets when subjected to test pressure. 
The rubber fabric hose originally in the umbilical cord was replaced by high-pressure hose 
with a seamless nylon core, a flexible braided nylon reinforcement, and a polyurethane jacket. 
The gas supply and compressed-air hoses were 3/4 in. I.D. and the gas-sampling hose 1/4 in. 
I.D. 

In the course of replacement of the hose components, two additional power cables for un- 
derwater photographic lights and a cable for remote camera control were added to the umbili- 
cal cord. In lieu of the original canvas jacket on the umbilical cord, the components on the 
modified cord were married together at 8-ft intervals. The umbilical cord was stowed on the 
platform on top of Sealab II when it was towed or transported on a barge. A circular protective 
enclosure on top of the "conning tower" was provided for stowing the umbilical cord; however, 
it was not adequate for stowing the enlarged cord. 

The upper end of the umbilical cord terminated at a central point on the stern of the sup- 
port vessel and connected to the various supplies of gas, air, and power, and to the communi- 
cation circuits. 



SYSTEMS 

Ballast System 

The ballast system was designed with sufficient compartmented liquid ballast to permit 
adjustment of weight and of center of gravity for several conditions. First, sufficient positive 
buoyancy and stability were required for towing Sealab II to its site. Second, positive buoy- 
ancy, stability, and freeboard were required when the vessel was moored on the surface at the 
site with the upper hatch open. During lowering of the vessel, a negative buoyancy was re- 
quired, but such as not to cause undue strain on the lowering gear. In place on the bottom, the 
vessel requires sufficient negative buoyancy to overcome that added by blowing water from the 
entry skirt, and enough negative buoyancy with its center of gravity well between the legs to be 
stable on the bottom in the prevailing current. The above conditions were to be satisfied with 
inside ballast tanks, with soft boundaries between the tank space and the pressurized habitation 
space, together with limited external ballast. This habitation space was to be pressurized be- 
fore lowering, so provision had to be made to prevent damage to the tank boundaries. These 
conditions were satisfied with an internal ballast tank in the upper portion of the main cylinder, 
extending its entire length and subdivided into three compartments, and a conning tower of 
sufficient size to double as tank and provide on-surface entry. 



ENGINEERING EVALUATION 315 

Provision was made to flood each tank space at its bottom, and all tanks were vented 
through individual valves to a common manifold which led to a master vent valve. The mani- 
fold was further connected to the main cylinder through a valve to provide pressure equaliza- 
tion between any tank and the habitation space. The manifold was also connected to the entry 
skirt to provide for blowing the skirt and equalizing the skirt with the habitation space. 

The weights and centers of gravity were calculated for all operational conditions, and a 
surface waterline was established. After all gear was aboard in its proper location, Sealab II 
was put into the water dockside, and the pig ballast under the topside walkway was adjusted to 
attain the pre-established water line. 

With all ballast tanks dry and the entry skirt flooded and hatches sealed, Sealab II was in 
condition to go to sea with buoyancy and stability as required for towing. On site, the conning- 
tower hatches could be opened to allow final checkout of equipment. The conning tower pro- 
vided the necessary freeboard to prevent flooding of the habitation space by wave action. Be- 
fore the habitation space was pressurized with its atmosphere, the end tanks overhead could be 
flooded. In this condition, buoyancy with hatches sealed was adequate to keep Sealab II afloat 
while it was pressurized. With the end tanks full, all flood valves were to be closed and in- 
ternal tanks were to be opened to the vent manifold, with the manifold open to the habitation 
space. In this way, during atmosphere pressurization, no pressure differential would exist on 
the boundary between the habitation space and the internal tanks. After pressurizing of the 
hull to slightly below the final pressure, the conning tower could be flooded to give the system 
negative buoyancy for lowering. Once on the bottom, the center overhead tank was flooded to 
stabilize Sealab II on the bottom and allow blowing of the entry trunk. While the center tank 
was flooding, its vent could be opened via the manifold to the interior; the vented gas then gave 
the habitation space its final desired pressure. 

For return to surface after all hatches were sealed, provision was made for blowing the 
center overhead tank and hoisting to surface. 

Electrical System 

Supply Voltage — The electrical distribution system used in Sealab II was 450 volts three- 
phase and 208/120 volts three-phase with ungrounded neutral. The system had a total capacity 
of 75 kva. Normal power was supplied from shore at 4160 volts three-phase by an underwater 
cable. The 4160-volt power terminated in an underwater transformer bank and was stepped 
down and supplied to Sealab at 450 volts three-phase. Alternate power for use in case of nor- 
mal power failure was supplied from the support vessel at 450 volts three-phase through a 
cable in the umbilical cord. Both cables entered the hull through pressure-proof stuffing tubes 
near the bottom of the hull. Both supplies were connected to the main power-distribution panel 
through 100-ampere three-pole circuit breakers. A mechanical interlock assembly was pro- 
vided so that both supplies could not be used at the same time. Indicator lights on the main 
panel indicated from which source power was available. 

Utilization Voltages — The electrical loads in Sealab II utilized the following voltages: 

1. 440 volts, three-phase 

2. 208 volts, three-phase 

3. 208 volts, single-phase 

4. 120 volts, single-phase. 

A transformer bank consisting of three 25-kva single-phase transformers connected delta-wye 
supplied the 208/120-volt power. The transformer bank was installed in a gas-tight compart- 
ment to prevent atmospheric contamination in case of transformer overheating. The hull 
formed one side of the compartment and was left uninsulated to aid in cooling the compartment. 
A fan was installed in the compartment to improve air circulation and provide additional cool- 
ing. A remote -reading thermometer was also installed so that the interior temperature of the 
enclosure could be monitored. The transformer bank and all equipment operating on 440 volts 
were supplied from the main distribution panel. Three low-voltage power panels were supplied 
from the load side of the transformer bank. Two of the panels supplied all of the 120 -volt 



316 



ENGINEERING EVALUATION 



SHORE POWER 

AT SCRIPPS 

!tl60 VOLTS 3 PHASE 



SUPPORT VESSEL 
POWER 
450 VOLTS 3 PHASE 



WATER HEATER 

7.6 KVA 

450 VOLTS 3 PHASE 



I 



UNDERWATER 
TRANSFORMER BANK 
4160 TO 450 VOLTS 



I 



LJ 



MAIN POWER 

DISTRIBUTION PANEL 

AND 

TRANSFER SWITCH 

THREE PHASE 

50 VOLTS 100 AMPS 



BASEBOARD HEAT LOAD 

16.7 KVA 
450 VOLTS 3 PHASE 



ARAWAK UNIT NO. 1 

TWO 1 HP MOTORS 
450 VOLTS 3 PHASE 



J 



1 



ARAWAK UNIT NO. 2 

TWO 1 HP MOTORS 
450 VOLTS 3 PHASE 



TRANSFORMER BANK 
75 KVA 3 PHASE 
i50 TO 208/120 VOLTS 



POWER AND LIGHTING 
DISTRIBUTION PANEL 
120 VOLTS 



I 



POWER AND LIGHTING 
DISTRIBUTION PANEL 
120 VOLTS 



POWER 
DISTRIBUTION PANEL 
208 VOLTS 



Fig. 123. Sealab II electrical system block diagram 



circuits, while the third panel supplied the 208-volt circuit. Figure 123 is a block diagram of 
the electrical power distribution system. 

Branch Circuits and Loads —All electrical circuits were controlled and protected by cir- 
cuit breakers located in the distribution panels. Wiring was installed in accordance with Gen- 
eral Specifications for Ships of the U.S. Navy, with the use of standard Navy shipboard cable 
and equipment. The electrical circuits were ungrounded to eliminate shock hazards. Figures 
124 and 125 show the power and lighting systems. Table 45 shows the total connected load of 
the electrical power-consuming equipment installed in Sealab II. 

Interior Lighting — The interior lighting fixtures were marine type fixtures using com- 
mercial 40-; 50-, 75-, or 100-watt lamps (A-19 bulb size). These lamp sizes were all tested 
to ascertain their ability to withstand pressures twice that equivalent to the water depths of 
200 ft (approximately 178 psi). All fixtures were controlled by conveniently located toggle 
switches. A red standing light was installed in the berthing area for low-level lighting. Indi- 
vidually controlled berth lights were installed for each berth. 



ENGINEERING EVALUATION 



317 



1 



u 



A J 




fe 




Ir 



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._! 



L-^ 



M 
U 



sL S 



0) 

o 
a 



XI 
(U 










o 



as 



X 
CD 



r—t 

nj 
(U 

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CM 



318 



ENGINEERING EVALUATION 

Table 45 
SEALAB II - TOTAL CONNECTED ELECTRICAL LOAD 



Load 


Volt-Amperes 


Voltage 


Interior Lighting 


2450 


120 


Exterior Lighting 


6000 


120 


Electric Blankets 


1800 


120 


Berth Lights 


250 


120 


General Purpose Outlets: 






1. Berthing 


1500 


120 


2. Galley 


2640 


120 


3. Laboratory 


4426 


120 


Refrigerator-Freezer 


1224 


120 


Arawak Units 


3168 


440 


Water Heater 


7600 


440 


Range 


4800 


208 


Ventilation 


1345 


120 


Heat 






1. Radiant Heating 


5000 


120 


2. Floor Heating 


4950 


208 


3. Convection Heating 


16,700 


440 


TV Control Rack 


1800 


120 


Total 


65,653 





Emergency interior lighting was provided by relay-operated and manually operated hand 
lanterns. The relay-operated lanterns would turn on automatically if there were a power 
failure. 

Exterior Lighting — Exterior lighting was provided by six 1000-watt incandescent standard 
Navy diving lights. These lights were installed on adjustable mounting brackets on the exterior 
hull of Sealab II. The mounting brackets were constructed so that the lights could easily be re- 
moved and used as far as 150 ft av/ay from the hull. The individual lights were connected by 
underwater connectors to a pigtail, which entered the hull through the instrumentation cable 
trunk, after Sealab II emplacement on the bottom. Each light was controlled by a switch located 
inside the Sealab. 



Ventilation System 

The ventilation system was designed to provide the following functions: 

1. Removal of carbon dioxide (CO2) 

2. Removal of odor, hydrocarbons, and aerosols 

3. Atmospheric circulation and distribution 

4. Make-up gas mixing. 

The CO2 scrubber consisted of 12 lithium hydroxide (LiOH) canisters arranged in the par- 
allel configuration, with a design capacity of approximately 540 man hours of operation per 12 



ENGINEERING EVALUATION 319 

canisters. The design flow capacity of the CO 2 scrubber was approximately 60 cfm. At this 
flow rate, complete circulation of the atmosphere (4000 cu ft) would require 66 minutes. The 
charcoal filter consisted of two units containing approximately 1400 cu in. of charcoal each. 
The filters were rechargeable and were sized to operate for approximately ten days before re- 
placement. Six filtei units were supplied. The design flow capacity of the charcoal filter was 
250 cfm. Complete circulation of the atmosphere through this filter would require 16 minutes. 
Of this total flow, tO cfm was drawn through the CO2 filter. The remaining 190 cfm was drawn 
through the water-closet compartment and generally from the galley area. This arrangement 
served to control odors in the water-closet compartment (where the sanitary drains were 
vented) and to remove any hydrocarbons produced in cooking. 

Atmosphere circulation was accomplished with a centrifugal blower powered by a 1/2- 
horsepower electrical motor. The normal power input to the fan was doubled because of the 
increased density of the ambient atmosphere, approximately twice that of standard air. Dis- 
tribution was accomplished through a single fore-and-aft duct, with one overhead grill in each 
of the four areas. 

Make-up gas mixing was provided for by introducing make-up helium or air into the vent 
plenum upstream of the blower. Make-up oxygen was introduced into the discharge duct at the 
point of highest velocity (see "Oxygen System," later in this chapter). 

Although specified in the "air conditioning package," time and budget did not allow integra- 
tion of the humidity control system. Three dehumidifiers were installed in Sealab II, each hav- 
ing a rated capacity, at standard conditions, of 47 pints per day, and one portable unit of like 
capacity was provided as a back-up. Two of the three installed units were located for intake of 
wet atmosphere from the entry area and discharge into the lab area. The third unit was located 
in the galley area to remove moisture produced in cooking and washing. A design control level 
of 70 percent relative humidity was selected to insure reliable operation of the "Krasberg" 
oxygen partial-pressure sensors for the total test period, based on manufacturer's recom- 
mendations. 

Heating System 

The heating equipment specified as a part of the air-conditioning system was omitted be- 
cause of space limitations. The living space was heated by means of electrical convection 
heaters mounted on the shell, radiant deck heating, and overhead radiant heaters. A total of 
26.65 kw of electrical heating capacity was provided, based on extrapolation of data obtained 
from Sealab I and the heat-loss calculations shown in Appendix B. The capacity of the heating 
system was increased to provide approximately 50 percent more heat input than indicated by the 
heat-loss calculations. Further, it was anticipated that as much as 20 kw of sensible heat might 
be realized from operating equipment in Sealab such as lights, electronics, motors, pumps, 
and fans. This overdesign was considered to be extremely desirable in the event of possible 
failure of portions of the heating system. 

The convection heating system was designed for connection to the 450-volt, three-phase 
line. Two commercial 240-volt baseboard heaters were connected in series, and three such 
groups were then connected in delta to the three-phase power. Separate banks were installed 
in the berthing, galley, and lab areas and were controlled by individual thermostats. Of the 
total heating capacity, 16.7kw was provided by the convection heaters. 

The radiant heating of the deck was provided by embedding mineral insulated heating cable 
in the concrete deck in the berthing, galley, and lab areas. The entire system was controlled 
by a single thermostat with its sensing element embedded in the concrete deck. A total of 
4.95 kw of the heating capacity was provided by this system. 

Four 1250-watt overhead radiant heaters were installed in the entry area and in the after 
end of the lab area. These units provided quick heat for warming up after showers and outside 
sorties. The heaters were controlled by individual off-on switches. 



320 



ENGINEERING EVALUATION 



Breathing-Gas Systems 

General — The primary breathing (atmosphere) gases for Sealab n were stored externally 
in 24 standard 1300-cubic-foot bottles at a nominal pressure of 2400 psig. All high-pressure 
lines were designed for 3000-psi service, and all low-pressure lines for 400 psi. A gas- 
control panel was installed above the communication center on the port side of the lab area to 
provide centralized control and monitoring of all gas systems, with the exception of the emer- 
gency breathing (Bibb) system. The Bibb system controls were located in the galley area for 
utmost convenience in the available space. All pressure regulators were of the standard weld- 
ing type, which were easy to obtain and which permitted easy adjustment at ambient pressure. 
Three identical regulators were used. They were interchangeable and required a minimum 
stock of spare parts. 

Oxygen System —An on-board oxygen supply of 14,300 cu ft was provided as the primary 
breathing supply. The oxygen system was installed essentially as shown in Fig. 126. The pri- 
mary oxygen system was automatic in operation and was controlled by the Krasberg oxygen 
partial-pressure sensor. This unit monitored oxygen partial pressure and in turn controlled 
an electrically operated solenoid valve to admit oxygen as needed. Remote readouts were pro- 
vided on the surface vessel for topside monitoring. Two separate, manually selected supplies 
of oxygen were available. 



SCRUBBER FILTER 
EXHAUST PLENUM s." 

POa SENSOR aT 
(115 VAX.) . ■ 



AUTOMATIC 02 MAKE -UP 



MANUAL 02 MAKE-UP 



MANUAL 02 MEASUREMENT 
2-200 CU. FT BOTTLES 




;l_ 



SERVO VALVE 

DISTRIBUTION 
DUCT 



GAS FLOW 



NOTE: 

GAS SAMPLING 

LINE TO BE 

UPSTREAM 

OF 02 MAKE-UP 



^ GAS CONTROL 
PANEL 



-STUFFING TUBE 






tlZX?^ 



-HULL (BOTTOM) 
' 02 STORAGE, EXTERNAL, 11-1300 CU.FT 
BOTTLES ON TWO MANIFOLDS 



yy^ln^ 




Fig. 1Z6. Sealab II oxygen system 



A secondary, manually operated system was included as a backup in the event of failure of 
the automatic system. 

The primary input of oxygen was directed into the discharge of the ventilation system to 
provide thorough mixing. This point of introduction also prevented high oxygen concentrations 
in the immediate vicinity of the blower motor. An input directly into the atmosphere was pro- 
vided for use in the event of failure of the blower system. 



A third oxygen-supply system was tied into the manual oxygen system so that emergency 
oxygen could be supplied from the surface. This supply would utilize the gas-sampling system 
via the umbilical cord. 



ENGINEERING EVALUATION 



321 



A pressure-relief valve (400 psig) was installed in the low-pressure portion of the oxygen 
system (immediately downstream of the pressure reducer). The pressure relief valve was 
discharged overboard through the benthic wiring trunk. A flow meter was installed in the oxy- 
gen input line to provide a visual indication of flow rates. 

Helium System — A total of 13,000 cu ft of helium was provided in the on-board supply. 
This helium was intended for use in make-up of any losses due to leakage and absorption and 
also to adjust the water level in the entry trunk. The helium system was installed essentially 
as shown in Fig. 127. The helium was introduced into the blower intake of the ventilation sys- 
tem to insure adequate mixing with the atmosphere. 



SCRUBBER- FILTER 
EXHAUST PLENUM 



HELIUM MAKE-UP-, 



LP 0-300 PSI 
3000 PSI H.P 



-GAS CONTROL 
PANEL 



PO2 SENSOR 

d^ t 

GAS FLOW 



fy^ 



STUFFING TUBE 



■3^ 



-HULL (BOTTOM) 



He STORAGE, E XTERNAL , 10-1300 CU. FT. 
BOTTLES ON MANIFOLD. 




Fig. 127. Sealab II helium system 



An additional helium system for initial charging and emergency make-up was installed as 
shown in Fig. 128. This system was supplied from the staging vessel through the umbilical 
cord. 

Emergency Breathing System — An emergency breathing (Bibb) system was installed to 
provide emergency premixed breathing gases in the event that the habitat atmosphere became 
contaminated (Fig. 129). The system would provide approximately 43 minutes' breathing time 
for ten aquanauts. Three standard 1300-cu-ft cylinders of premixed gas were valved into a 
regulator located in the galley area and supplied eight manifolds containing four quick- 
connective outlets. Twelve Calypso model 1050 single hose scuba rigs, modified by removal 
of the first- stage pressure regulator and the addition of a quick-connective fitting, were pro- 
vided for use with the Bibb system. 



In addition to the Bibb system, twelve 38-cu-ft scuba bottles with first-stage regulators 
(removed from Calypso rigs) and quick-connective fittings identical to those on the Bibb mani- 
folds were provided near the entry trunk. These bottles were to be utilized by the aquanauts to 
swim to the Personnel Transfer Capsule (PTC) in the event of emergency evacuation of the 
habitat. 



322 



ENGINEERING EVALUATION 



OXYGEN MAKE-UP 8. GAS SAMPLING 



SCRUBBER-FILTER 
EXHAUST PLENUM 



DISTRIBUTION 
DUCT. SEE DWG. 
NO. C-8747) 




TO 1/4 I.D. GAS 
SAMPLING HOSE 
(APPROX. 30'L0NG) 



STUFFING TUBE 




TO UMBILICAL 
CONNECTIONS TOPSIDE 



HULL (BOTTOM) 



Fig. 128. Sealab II emergency 
helium, air and oxygen system 



Gas-Sampling System 

A gas-sampling system was designed to allow topside monitoring of the atmosphere of 
Sealab II. This system allowed sampling throughout the interior and in the ventilation plenum. 
The gas- sampling intake was located in the outlet of the ventilation system, upstream of the 
oxygen input, in order to obtain samples of well-mixed and filtered atmosphere. An additional 
gas-sampling intake was provided via a 30-ft length of 1/4-in. I.D. hose for sampling at any 
desired point inside the Sealab. The gas-sampling system was connected to the Atmosphere 
Control Van on the surface vessel via the gas-sampling hose in the umbilical cord. The gas- 
sampling system also doubled as an emergency oxygen supply from the surface. 



AFT TO QUICK-CONNECT 
OUTLETS (AUTO. SHUTOFF) 
12 OUTLETS IN ENTRY 
SPACE a 4 IN LAB. SPACE 



EMERGENCY 
BREATHING 
MANIFOLD 



3000 PS I HP 



-? 



L.PO-300 
PSI (120 
PSI NOM) 



FWD. TO QUICK -CONNECT 
OUTLETS (AUTO, SHUTOFF) 
"12 OUTLETS IN BERTH SPACE 
a 4 IN GALLEY SPACE 



■GAS CONTROL 
PANEL 



^STUFFING TUB 



USE 
— HULL (BOTTOM) 



He (85%) -02 (15%) PREMIX STORAGE, EXTERNAL, 
3-1300 CU. FT BOTTLES ON MANIFOLD 






Fig. 129. Sealab II Bibb system 



ENGINEERING EVALUATION 323 

Arawak System 

The Arawak system was utilized to pump the Sealab atmosphere to a swimmer through a 
hose. As the swimmer exhales, the gas is returned through a second hose to the Sealab II at- 
mosphere for reprocessing. The equipment installed in the Sealab consisted of two positive- 
displacement, carbon-vane pumps driven by separate one-horsepower electric motors. One 
pump, operating at approximately 23 psig, supplied breathing gas to one swimmer while the 
other pump, operating at a negative pressure of approximately 15 in. Hg, returned the exhaled 
gases to the Sealab. This equipment was mounted overhead in the entry area. Two complete 
systems were installed, with cross connections to provide continuing operation in the event of 
failure of either system. 

Plumbing and Sanitary System 

The plumbing and sanitary systems were essentially of conventional design. The plumbing 
system was designed to operate at a pressure of approximately 40 psi over ambient, with 
pressure-relief valves set at 100 psi over ambient. All fixtures were conventional; the water 
closet was a marine type utilizing sea water for flushing. The sanitary system was a gravity- 
flow system, with direct overboard discharge. The discharge openings were kept below the 
water level in the entry trunk in order to prevent atmosphere loss. All fixtures were trapped. 
Sanitary lines were vented inside the habitat into the charcoal filter of the ventilation system 
to eliminate odors. The water closet was connected to one sanitary drain and all other fixtures 
(lavatory, two sinks, and two showers) to the second drain. Flexible hoses 50 ft long were at- 
tached to the sanitary discharge openings to carry the effluent away from Sealab II. Water was 
supplied from shore through two 3/4-in. plastic (PVC) pipes approximately 3,500 ft long. Shore 
water pressure could be varied from approximately 70 to 100 psi and was metered to determine 
usage rates. An emergency fresh-water tank of 150-gallon capacity was provided in the event 
of interruption of the shore supply. This tank was not pressurized and was not connected to 
the normal water system. 

Communication System 

Communication between Sealab II and the Command Control Center on the support vessel 
was provided by a communication cable in the umbilical cord. The cable terminated in patch 
panels in the habitation space and in the Command Control Center. Receptacles were utilized 
in the patch panels to facilitate connecting the various pieces of equipment at the test site. The 
following modes of communication and instrumentation were provided: 

1. Helium Speech Unscrambler - three circuits 

2. Electrowriter, two-way 

3. Television - closed circuit monitoring 

4. Television - aquanauts' entertainment 

5. Audio - intercom, two-way 

6. Audio - carrier-transmitted two-way voice communication between support vessel and 
shore (via Sealab and benthic lab) 

7. FM music - aquanauts' entertainment 

8. Wedge spirometer output 

9. Oxygen partial pressure 
10. Open microphones. 

The patch panel in Sealab 11 was located in an area on the port side of the laboratory des- 
ignated the communication and watch center. All communication with surface control originated 
at this point, except two helium speech unscrambler circuits, which were installed in the galley 
and berthing area. The primary purpose of the two additional helium speech unscrambler 



324 ENGINEERING EVALUATION 

outlets was to permit unscrambled speech communication between aquanauts. FM music and 
commercial television signals were provided for entertainment. FM speakers were located in 
the berthing area and the laboratory area and were provided with individual volume controls. 
The entertainment TV was located in the laboratory area and had the video tube enclosed in a 
specially designed, pressure-proof container. 

Three open microphones were installed in the laboratory, living quarters, and galley for 
continuous monitoring of conversations of the aquanauts. A commercial two-way intercom was 
used to pass information from the surface and for limited two-way conversations. The system 
consisted of a master unit in the topside Command Control Center and a slave unit below. 

The oxygen partial pressure output from the Krasberg oxygen control unit was transmitted 
to the Atmosphere Control Center through the Command Control Center. The output of the 
wedge spirometer transducer, a device for measuring the flow and volume of the lungs, was 
also transmitted to Atmosphere Control Center. Data from other experiments and tests were 
transmitted to the surface on the wedge spirometer conductors on a time-sharing basis. 

The signals from three closed-circuit TV cameras were transmitted to the Command Con- 
trol Center via a single coaxial cable at three different frequencies. 

Data-Recording System 

To obtain data which would aid in future Sealab designs, provisions were made in Sealab II 
to record certain engineering and environmental data. It was originally planned to transmit 
some of this data to shore through the facilities of the benthic lab, but technical difficulties 
prevented its use. The following data were recorded by hand on preprinted forms by the per- 
sonnel on watch: 

1. Power consumption 

2. Equipment running time 

3. Temperature, interior 

4. Temperature, equipment 

5. Humidity, interior. 

Power -consumption figures were obtained from a commercial three-phase kilowatt-hour meter 
installed on the load side of the main transfer switches. 

Equipment running time was recorded for the following equipment: 

1. Water heater 

2. Dehumidifiers (4) 

3. Baseboard heating banks (3) 

4. Deck heating 

5. Overhead radiant heaters (4) 

6. Refrigerator 

7. Freezer. 

Elapsed-time meters for the above equipment were installed in a convenient panel near the 
watch center to facilitate recording of data by the man on watch. 

Temperature sensors were installed in the entry area, lab area, galley, and berthing area, 
and in the refrigerator and freezer compartments. The sensors were connected to millivolt- 
to-current converters. The outputs of the converters were shunted by a resistor to obtain a 
to -6 volt dc output. The output from the resistor of each converter was connected to a 
high-input-resistance voltmeter through a selector switch. This readout meter was located 



ENGINEERING EVALUATION 325 

adjacent to the time-lapse panel, and the voltage analog of the temperature was recorded on the 
preprinted data forms. 

Humidity sensors were installed in the entry, lab, galley, and berthing areas. The humidity 
system was similar to the temperature system described above, except for the sensors and a 
signal converter connected between the sensors and the millivolt-to-current converters. The 
voltage analog of the humidity was obtained from the meter used in the temperature system. 
The humidity sensor in the entry area failed to operate after Sealab II was placed on the bot- 
tom, and no data were obtained from this sensor. 

It would not have been necessary to change the output of the MV/I converters to a voltage, 
but this was done to permit the output information to be telemetered to shore via the benthic lab. 

EQUIPMENT 

General 

All equipment installed in Sealab II was checked and certified for use in the operational 
environment. Particular emphasis was placed on the elimination of materials which might in- 
troduce toxic fumes into the closed atmosphere. All equipment cavities and enclosures were 
either vented for pressure equalization or were proven to be capable of withstanding 1-1/2 
times the ambient pressure of the Sealab II atmosphere. Performance characteristics were 
checked in artificial Sealab environments to ensure required operational performance. All 
equipment used in Sealab II was essentially "off-the-shelf" hardware. 

Refrigerator- Freezer 

The refrigerator-freezer was a Navy "standard stock" item with refrigerator and freezer 
capacity of five cubic feet each. The two refrigeration systems were of conventional mechani- 
cal (Freon) type and were powered by 1/6-hp electrical motors. Insulation consisted of four 
inches of spun fiber glass. In order to reduce heat losses in the helium-rich atmosphere, two 
inches of cork insulation was added to the outer surfaces of the cabinet. The standard aneroid 
temperature-sensing elements, which would not operate properly at hyperbaric pressures, 
were replaced with mercury sensors. These were well protected to reduce the possibility of 
rupture and spillage of mercury. 

Cooking Equipment 

The cook top for the galley consisted of four heating units installed in the counter top. 
Each unit had a heat-control switch. The units were rated at 1250 watts at 220 volts; however, 
the supply voltage was only 208 volts and the maximum output approximately 1180 watts each. 
A commercial 1500-watt rotisserie and four-slice standard Navy toaster were also included in 
the galley equipment. 

Water Heater 

The water heater was a Navy "standard stock" type with a storage capacity of 50 gallons 
and a recovery rate of 50 gph. Maximum power consumption was rated at 7.6 kw. A 
temperature-and-pressure-sensitive pressure-relief valve was installed and set for a relief 
pressure of 100 psig. No special insulation was added to the water heater. 

DISCUSSION AND TEST RESULTS 
Hull 

General — The hull appeared to be leak free and structurally adequate, and generally per- 
formed its function well. There was little evidence of corrosion or marine fouling. 



326 ENGINEERING EVALUATION 

Ports — The viewing ports in the laboratory and galley were utilized extensively to observe 
swimmers in the water (visibility permitting), to monitor the interior with externally mounted 
TV cameras (helium permeation of the TV monitors necessitated removal from the interior), 
and to provide a diversion in the form of fish watching. The viewing ports presented several 
problems, as follows: 

1. The flat gaskets installed on the internal pressure-tight covers leaked (four out of 
eleven ports), preventing full pressurization of the hull on the surface as intended. 

2. Opening and securing of the internal covers was a time-consuming task because of the 
number of bolts and the torque required to pull down the gaskets. 

'3. The swing of the internal covers consumed excessive space inside the hull. 

4. Removal and replacement of the external port covers was a difficult and hazardous op- 
eration because of their size and weight. 

5. The cold inside surface of the port light caused moisture condensation, resulting in wet 
areas around the ports. 

Access Openings — The main access hatch performed its intended purpose well, with no 
evidence of leakage. Some of the aquanauts had difficulty in entry and exit through this hatch. 
However, it seems that these difficulties stemmed primarily from lack of space in the entry 
area and the necessity of climbing the entry ladder in full swimmer dress. 

The surface access hatch was useful for the final systems checkout on surface and for the 
last-minute stowage of gear. Minor problems associated with this hatch were the lack of 
counterbalance, making hatch operation difficult, and moisture condensation on the cold surface 
of the uninsulated hatch, which dripped on the walkway. As a remedy, a plastic sheet was 
stretched underneath the hatch to shed the water to one side of the walkway. 

The emergency access hatch was fortunately not required. This hatch is considered too 
inaccessible to serve its intended purpose. 

Entry Trunk — The entry trunk provided ample displacement volume for internal pressure 
changes and water-pressure variations due to tidal action. The six-foot tidal range experi- 
enced was somewhat less than the predicted nine-foot range. The maximum recorded water- 
level excursion was less than two feet. 

Shark Cage — The shark cage, provided for swimmer protection, served little useful pur- 
pose in this test, since sharks were not a problem. 

Support Structure — The support structure served its intended purpose with little evidence 
of sinking into the sea bottom. However, because of a late change in site location, the Sealab 
was placed on an uneven bottom, causing the craft to assume a final attitude having a 6-degree 
port list and a 6-degree bow-up angle. 

Hull Penetrations — No significant problems were encountered with hull penetrations. 

Variable Ballast — The ballast tanks, generally, functioned as intended. However, difficul- 
ties with the associated piping and valving were encountered, as discussed under "Ballast Sys- 
tem," later in this chapter. 

Hull Insulation — The cork insulation used in Sealab II functioned well. The average heat 
input (60,000 Btu) required to maintain the design temperature (88° F) agreed very closely with 
the theoretical calculations of heat loss (54,300 Btu). Some additional heat losses not consid- 
ered in the design calculations were the heat of warm water drained overboard, Arawak gas 
heat, and electrical transformer heat losses to sea. Minor damage to the insulation was caused 
when the Sealab partially flooded during the final raising operation. 



ENGINEERING EVALUATION 327 

Umbilical Cord 

No problems were reported with the umbilical cord as assembled at Long Beach Naval 
Shipyard. Since supporting floats were married to the umbilical cord as it was streamed, han- 
dling at the test site was cumbersome and time consuming. 

Systems 

Ballast System — In actual operation, certain problems developed in using the system as 
designed. First, when the end overhead tanks were flooded on surface, trim was difficult to 
control. These tanks flood independently, and one tends to fill faster than the other. As it 
does so, that end trims down, increasing the head on the flood valve, accelerating the out-of- 
trim conditions. Ultimately, the flood valve on the high end broaches and the tank will not fill 
further. When this happened the tank on the high end was filled by hand from buckets. In the 
future, provision should be made for better control of flooding of longitudinally flooded tanks. 

A further difficulty was encountered in blowing the center overhead tank prior to surfacing. 
Sealab was in an inclined position on the bottom, and there was no valve opening on the low edge 
of the tank. It was therefore impossible to blow all the water out. Some water then had to be 
blown from the end tanks to remove enough weight to surface. As there was no way of deter- 
mining the volume of water in any of these tanks when partially full, it was impossible to con- 
trol trim, and when Sealab II surfaced, it was at about a 30-degree angle. An improved system 
of blowing tanks is necessary to assure complete removal of water from tanks when desired. 

Electrical System — The electrical system as a whole functioned satisfactorily and intro- 
duced few problems. The power capacity provided appears adequate on the basis of power 
consumption during the underwater test phase (see Tables Al, A2, A3, and A4, in Appendix A). 
The maximum average power requirement was 38.8 kw. There are long intervals between 
readings during this period, and it appears that some error entered the readings of the watt- 
hour meter. Since a recording wattmeter was not used, the instantaneous peak-power require- 
ment is not known and could have been much greater than the maximum average peak load. 
The average daily power requirement for the 42-3/4-day period was 21 kw. In any case, a 
maximum of 75kva at unity power factor certainly appears ample. 

The only major problem experienced with the electrical system was with the external 
lighting. The short life of the 1000-watt incandescent bulbs (rated 50 hours) necessitated fre- 
quent bulb changing, which proved to be a time-consuming job. The lighting level was not suf- 
ficient for photography; however, this was not the original intention of the external lighting. 
Some trouble was experienced by the aquanauts in identifying the proper underwater pigtail 
connector to be utilized for connecting each exterior light. 

The main complaint concerning the interior electrical system was the location and insuffi- 
cient number of convenience outlets in the lab area. Also, the level of the interior lighting was 
not sufficient for photography. Here again, the interior lighting was not designed for this 
purpose. 

There were no apparent problems with the thermal-magnetic circuit breakers. The high 
thermal conductivity of helium affects the thermal characteristics of this type of breaker and 
probably does not provide the proper overload protection for the electrical circuits. The high 
conductivity of the helium atmosphere also works in favor of electrical equipment, in that they 
can operate at higher currents without danger of overheating. 

Ventilation System — The ventilation system of Sealab II provided for satisfactory mixing 
of make-up oxygen, helium, and air. The four dehumidifiers, with a total rated capacity of 
23.5 gallons of water per day, actually condensed an average of only about three to four gallons 
per day. The fan motors of the dehumidifiers were replaced by 1/4-hp motors to provide addi- 
tional load capacity required by the increased density of the Sealab atmosphere. The poor per- 
formance of the dehumidifiers caused difficulty in controlling the humidity during periods of 
peak moisture input. Table A4 indicates an average relative humidity of 72.1 percent, but with 
relatively wide excursions as shown in Fig. A7. 



328 ENGINEERING EVALUATION 

The poor performance of the dehumidifiers was not anticipated, but is attributed largely to 
inadequate cooling capacity. The specific heat of the Sealab II mixture of oxygen, helium, and 
nitrogen at approximately seven atmospheres pressure is about 32 times that of air at sea 
level (Appendix C). Hence, a much larger amount of heat must be removed from the Sealab II 
mixture than from air at the same temperature to effect the same dehumidification. The fact 
that the Sealab atmosphere was approximately six times as conductive as air tended to offset 
this difficulty but could not remedy it altogether. Other factors such as film coefficients and 
the dew point of the Sealab II atmosphere also tended to offset the specific -heat effect, but the 
extent is not known. 

The relative humidity was reduced considerably by the use of an automatic coffee urn for 
heating water for beverages rather than open pots. The radiant heaters in the entry area were 
turned off at night to reduce evaporation of sea water. 

The atmospheric circulation and distribution system was not adequate and contributed to 
the dehumidification problem. A higher flow rate and improved distribution of the atmosphere 
would have lessened the buildup of humidity in the berthing and galley areas and would have 
improved the evaporation of perspiration. Better moisture distribution should have permitted 
more uniform and efficient operation of the dehumidifiers. 

The performance of the carbon dioxide filter was acceptable but was somewhat less than 
satisfactory. Each set of lithium hydroxide canisters provided for only about 400 man-hours 
of operation rather than the design figure of 540 man-hours (75 percent saturation). This limi- 
tation aggravated an already severe handling and storage problem aboard Sealab II. A total of 
291 canisters of LiOH (1700 pounds) were used for 427.5 man-days of operations. One pound 
of LiOH should absorb one pound of CO 2. The average rate of production of CO 2 is approxi- 
mately 0.10 pound per man hour, or 2.4 pounds per man day. Hence, the efficiency of absorp- 
tion in the canisters was only 

428 man-days x 2.4 lb C02/day 
100 ^ 1700 lb CO 2/1700 lb LiOH = 60 P^^^^^t. 

The charcoal filters seem to have operated satisfactorily, since objectionable odors were 
not evident. These filters were well overdesigned by normal standards in order to provide for 
such anticipated but unknown quantities as high humidity, LiOH dust, internally vented sanitary 
systems, and contaminants from cooking at the high ambient pressures. 

Heating System — The heating system performed exceptionally well. As can be seen from 
Table A4, the baseboard heaters and radiant heaters 1 and 2 could have been omitted without 
affecting the comfort of the Sealab. The radiant deck heating proved ideal for Sealab and pro- 
vided a comfortable atmosphere. Radiant heaters 3 and 4, installed in the entry area, were 
used primarily for quick warmup after outside excursions. It should be noted that the total 
average heat requirement for Sealab II, approximately 60,000 Btu, was somewhat higher than 
indicated by heater operation, since essentially all electrical power except exterior lights (17 
kw average) was realized as sensible heat inside Sealab. 

Breathing-Gas Systems — The automatic oxygen system performed well, except that the 
solenoid valve chattered when the oxygen level fell just below the mean control level. This 
difficulty occurred during the first team's stay and was remedied by deenergizing the system 
until the oxygen level neared the lower control limit. At this point the system would be re- 
energized and allowed to replenish the atmosphere with oxygen to the upper control limit. 
Since the cycle time for this procedure was from one to two hours, it was not considered a 
major problem. The malfunction seemed to be caused by a faulty relay in the control system. 

During the third team's stay the pressure reducer failed, causing oxygen to be dumped 
overboard through the pressure-relief valve. Since the spare regulator furnished did not have 
the proper connections, the automatic system was secured. Subsequent oxygen input was con- 
trolled using the manual system. In addition, the emergency system was utilized to replace 
the lost oxygen from the surface. 



ENGINEERING EVALUATION 329 

The helium system performed satisfactorily. Approximately 20 percent of the onboard 
helium supply was used to replace losses through the sanitary drain discharge and by absorp- 
tion into the sea water. 

The emergency breathing system was not required. However, during on-bottom test pro- 
cedures, the pressure reducer did not provide adequate flow for all ten aquanauts simultane- 
ously unless the pressure was increased above the level compatible with the Calypso breathing 
apparatus. At the end of the test period, excessive corrosion was observed on all quick- 
connective fittings installed on the Bibb manifolds. The system could have been used in an 
emergency, but it was considered to be marginal. 

Gas-Sampling System — The gas-sampling system performed satisfactorily and caused no 
difficulty. 

Arawak System — Evaluation of the Arawak systems by aquanauts of each team indicated 
that the type of work to be done determined what breathing system was to be used. Team 1 
utilized the Arawak system approximately 50 percent of the time. The majority of the work 
required of the subjects was in the close proximity of Sealab. Minor repairs to the vacuum 
pump were accomplished by team members. 

Team 2 relied on the Arawak approximately 35 percent of the time. The subjects of this 
team ventured further away from Sealab. In general, no sorties of over 50 ft were conducted 
by aquanauts using the Arawak. Most Arawak sorties were local, being used for dumbwaiter 
transfers and general maintenance work on or in the vicinity of the Sealab. 

Team 3 utilized the Arawak system approximately 30 percent of the time. The majority of 
work assigned to this team was beyond the 100-ft length of the Arawak's hose. No maintenance 
was performed by subjects of Team 3. 

The primary problem encountered with the Arawak system inside Sealab was that of noise. 
The noise produced was that of intake and exhaust of the pumps making communications in the 
entry area most difficult when the Arawak was in operation. 

Plumbing and Sanitary System — Some minor difficulties were experienced with the sanitary 
drains. The discharge hoses attached to the drains were lighter in weight than those specified 
and required weights to hold them down and prevent the loss of atmosphere from the water- 
closet drain. This overboard discharge was shortened during fitting-out to reduce line restric- 
tion. This modification raised the hose-connection point abo'-e the entry-trunk water level, 
but below deck level. Some atmosphere loss was reported through the salt-water supply line 
for the water closet. Apparently the check valve malfunctioned. The manual pumping effort 
required for flushing the water closet was reported to be excessive. This effort was apparently 
greater than that required in Sealab I and was due to the smaller flushing capacity of the Sea- 
lab II water closet. Also the shower tubs would not drain, since the overboard discharge (star- 
board side) was trapped by the six-degree port list of Sealab. Drain holes were drilled through 
the port side of the tubs, allowing the water to drain overboard through the entryway. 

Water-usage rates were determined for the first team as shown in Fig. A2. Overall usage 
rates could not be determined, since the meters were not read regularly, and a leak which oc- 
curred in the line from Sealab to the surface vessel on Sept. 24 prevented the use of the final 
meter readings. 

Communication System — Considerable crosstalk was experienced between circuits in the 
communication system, even though shielded conductors were used in the communication cable 
of the umbilical cord. The exact cause of the crosstalk was not ascertained. It was found that 
the shielding of the conductors in the communication cable had not been carried through the 
patch panels. This failure may have been the problem. Some crosstalk may have been caused 
by improper shielding and shield grounding of conductors in the Command Control Center. 

The TV cameras became inoperative when high-pressui e helium apparently leaked into 
the interior of the cameras and placed the components undt. pressure. Although the camera 
seals were capable of withstanding pressures much greater than ambient, the helium apparently 



330 ENGINEERING EVALUATION 

permeated the rubber 0-ring seals and the glass lens. Replacement TV cameras were secured 
and placed outside the hull, looking through the ports on either side of the lab area. No further 
problems were experienced. 

The slave unit of the intercom became inoperative during the second week of the operation 
and was replaced by a master unit wired as a slave. This master unit became inoperative 
after two days of operation. The cause of the failures was not determined. A second master 
wired as a slave was installed and operated satisfactorily the remainder of the test. The 
original slave unit is nothing more than a permanent -magnet speaker and should not be af- 
fected by pressure. The master unit has a transistorized power supply and amplifier and pro- 
vides amplification for the slave unit. 

Although the electrowriter performed satisfactorily, some ink splattering occurred when 
the Command Control Center initiated messages. This condition may have been caused by the 
high ambient pressure. 

No problems were experienced with the entertainment TV and FM music equipment. 

Data-Recording System — The equipment of the data-recording system performed its in- 
tended function, with the exception of the humidity sensor in the entry area. The major prob- 
lem with the system was the necessity of recording the data by hand. As can be seen from 
examination of Tables Al, A2, and A3, data were recorded irregularly and in some cases not 
at all. The most complete data were obtained by the first team and is considered to be repre- 
sentative of the operation. 

Equipment 

Refrigerator- Freezer — The refrigerator was marginal in operation and definitely too 
small in storage capacity. As can be seen in Tables Al, A2, and A3, the refrigerator was ca- 
pable of lowering the temperature inside the compartment to the desired level of 42 °F during 
long periods when the compartment door remained closed. However, it did not maintain this 
temperature level during periods of frequent opening or normal turnover of stored items. One 
contributing factor was the upright design, which allowed the cold atmosphere inside to "fall 
out" each time the compartment door was opened. The circulating fan inside the storage com- 
partment would aggravate this effect whenever the door was opened during the "on" cycle. The 
major factors, however, were the high thermal conductivity and specific heat of the atmosphere. 

The freezer was not capable of producing the desired temperature of 5°F. As shown in 
Table Al, the lowest temperature reached was 16.9° F after three days of continuous undis- 
turbed operation. On Sept. 2, the freezer thermostat was readjusted to 38° F to provide addi- 
tional refrigerator volume. Freezer operation was affected by the same factors as the re- 
frigerator. 

Cooking Equipment — The aquanauts did very little food preparation, since most food was 
canned or precooked and required only reheating. The cook top and the rotisserie operated 
satisfactorily. The toaster would not toast bread in the helium atmosphere. 

Water Heater — The water heater performed satisfactorily, failing to meet the demand on 
only a few occasions. When the hot-water supply was exhausted, recovery was effected within 
a relatively short time, approximately 20 minutes. 

CONCLUSIONS AND RECOMMEInDATIONS 

Hull 

General — Although the Sealab II was not designed for full surface pressurization for depths 
greater than 280 ft, it can and should be utilized for deeper runs. With the installation of a 
suitable automatic or semiautomatic pressure-control system, the Sealab II hull could be uti- 
lized to the continental- shelf depth of 600 ft or more. 



ENGINEERING EVALUATION 331 

Ports — Since viewing ports in the berthing area and in the entry area were not utilized, 
these ports should be eliminated. The internal pressure-tight covers for the remaining ports 
should be redesigned for use of a radial squeeze O-ring seal. This change should eliminate 
the leakage problems and will allow the use of fewer bolts with less torque. 

Another desirable alteration is the design of viewing ports to withstand the required pres- 
sure differential. This end could be attained by using heavier, high-strength glass or by re- 
ducing the port diameter, or both. This alteration would eliminate the need for internal covers 
and for pressure equalization of the volume between the internal cover and the port glass. 
External covers would still be required for protection during Sealab handling operations. The 
external protective covers should be hinged to the port frame to reduce handling difficulty and 
improve diver safety. 

Access Openings — The emergency exit hatch should be made more accessible, possibly to 
the extent that it may be used as a secondary access hatch for resupply. This provision would 
relieve the congestion and traffic at the main access hatch. Improved bilge drainage in this 
area should be provided. 

The surface access should be provided with a counterbalance system for improved ease of 
opening and closing and a latch for securing when open. This hatch should also be insulated to 
reduce heat loss and to prevent moisture condensation. 

The main access hatch appears to be adequate without modification. One item to be con- 
sidered is a means of draining the bilge around the hatch thimble. 

Entry Trunk — As a means of providing much-needed additional space, the entry trunk 
should be enlarged and enclosed (nonpressure) for use as a diving station. This area should 
be used for: 

1. Entry and exit. 

2. Storage of diving gear. 

3. Donning and doffing of gear. 

Large viewing windows should be installed in the entry trunk to permit observation of the 
outside area and divers in the vicinity. These observation windows will eliminate the need for 
the shark cage. This modification, however, will depend on the following additional design 
considerations: 

1. Additional life-support requirements, including heat and atmosphere control and 
circulation. 

2. Increased buoyancy at the stern of the craft. 

3. A water-trapped entry arrangement of adequate displacement volume, which can be 
negotiated by the divers in full diving dress with a minimum of climbing. 

4. Downward extension of all open-ended hull penetrations to the lowered water level in 
the entry. 

A similar room at the emergency access hatch would serve for use as a resupply and ob- 
servation station. This arrangement would offset the increased buoyancy at the stern. 

Support Structure — In order to provide increased versatility in adapting the Sealab to 
varying bottom conditions, the supporting structure should incorporate a means of self-leveling 
when placed on the bottom. The operation of this leveling system should be completely auto- 
matic or require little diver support. One method of accomplishing this objective would be the 
use of four cross-connected hydraulic rams. When placed on the bottom, hydraulic pressure 
equalization between pairs of rams would allow the Sealab to trim itself. Stabilization of the 
system (hull and support or hold-down structure) would re^.uire closing only one valve in each 
of the two cross-connecting lines. These valves could be operated remotely from inside Sealab. 



332 ENGINEERING EVALUATION 

In addition, a hydraulic pump could be installed to provide final trim, if necessary. This type 
of system would be relatively fail-safe; loss of hydraulic fluid would only cause loss of trim, 
since the rams at full extension or collapse still provide a safe mechanical connection. The 
support or hold-down structure should be designed such that the height of the Sealab hull above 
bottom is minimized if visual observation of the bottom from inside Sealab is to be a consid- 
eration. 

Variable Ballast — In view of the problems encountered with the internal ballasting ar- 
rangement, and in order to provide additional usable internal volume, an external variable 
ballast system should be considered. The internal volume of the present ballast tanks could 
then be utilized as additional equipment and stowage space. 

Hull Insulation — Since the cork insulation used in Sealab II functioned quite successfully, 
it would seem to be the logical choice for use in Sealab HE. Other insulating materials are 
available, such as urethane foams, which offer increased thermal efficiencies (2 to 1) over 
cork at standard conditions. However, in the Sealab environment the theoretical efficiency of 
the foam is only 13 percent better than cork. In addition, one must carefully consider the dis- 
advantages of the foam, such as increased cost and possible toxicity. 

The Sealab hull could be insulated externally to eliminate the reduced thermal efficiency 
caused by the Sealab atmosphere. However, some new problems would be encountered; the 
material used must be relatively impermeable to water, must have the necessary compressive 
strength to withstand the ambient water pressure, and must be relatively rugged to withstand 
normal handling of the Sealab. 

The only insulation system which would seem to eliminate the effects of both the Sealab 
atmosphere and the outside water would be a double-shell arrangement similar to the "vacuum- 
bottle" principle. This system is considered not feasible from the standpoint of economic 
considerations. 



Umbilical Cord 

The umbilical cord should be designed as a composite unit. The design should provide for 
a smaller size, reduced weight, increased ruggedness, and self -buoyancy. A small reel should 
be provided for storage and improved handling of the umbilical, and Sealab hull connections 
should be provided to permit replacement of the entire umbilical when needed. A thorough re- 
view of conductor requirements should be made so that an adequate number may be provided. 
A generous number of spare condactors should also be provided for backup and nonessential 
use. 



Systems 

Electrical System — As has been pointed out, the electrical system as a whole was very 
satisfactory. It is recommended *hat the basic system be retained and that the following 
changes be made. 

1. Replace the present thermal-magnetic circuit breakers with hydraulic -magnetic type. 
These circuit breakers are commercially available but would require pressure testing and 
possible modification of the hydraulic tube. This type breaker is not temperature sensitive. 

2. Install multiple plug strips along the top of all lab benches. Connect the plug strips to 
existing circuits with portable cable and twist-lock plugs and receptacles. 

3. Redesign the interior lighting system to provide two levels of lighting, one for photog- 
raphy and one for normal use. Quartz-iodine lamps should be considered, since they are ca- 
pable of withstanding the ambient pressures expected. They can also be dimmed with com- 
mercially available dimmers; however, tests will be required to determine the effect of the 
helium-rich atmosphere on the bu'b temperature. The iodine cycle of the quartz-iodine lamp 
will not function below a certain temperature. To prevent burning the vidicon tubes of the TV 



ENGINEERING EVALUATION 333 

monitors, the fixtures for the interior lighting should be recessed overhead or constructed so 
that no light is emitted from the sides. 

4. Redesign the exterior lighting system to provide two levels of lighting, one for photog- 
raphy and one for normal use. Quartz-iodine type lamps should be used. The fixtures should 
be mounted with universal swivel mounts on short booms extending from the hull. Power out- 
lets which can be connected wet should be installed at each light location and each outlet con- 
trolled by a dimmer switch located inside Sealab. Fixtures with wet -bulb changing capabilities 
would be desirable. The use of mercury vapor lamps is not recominended, since they require 
auxiliary equipment and operate at voltages up to 400 volts. 

Ventilation and Heating System — It seems desirable to retain the radiant-deck heating sys- 
tem and some overhead radiant heating, which contributed much to the level of comfort in Sea- 
lab II. Otherwise the ventilation system should be completely redesigned as an integrated 
atmosphere-control or conditioning system. Ideally, this system should perform all 
atmospheric-control functions including ventilation, distribution, filtering, dehumidification, 
atmospheric replenishment, and temperature control (heating and cooling). This system must 
include adequate sensing and control equipment and should be specifically designed for use in 
the Sealab environment. The dehumidifiers must be capable of maintaining the required physi- 
ological comfort levels in the Sealab environment. Means should be provided for more efficient 
removal of carbon dioxide than in Sealab n. Means should also be provided for the removal of 
carbon monoxide and other trace contaminants which were not absorbed by charcoal or LiOH in 
Sealab II. 

Breathing-Gas System — As indicated above, the atmosphere-replenishment functions 
should be incorporated into the atmosphere-control system. The gas systems need improve- 
ments of control equipment, such as more reliable valves, more reliable regulators with 
higher flow rates and bypass circuitry, improved sensing and control equipment, and leak-free 
piping and storage systems. 

Since the emergency breathing (Bibb) system installed in Sealab n was considered mar- 
ginal, it is recommended that the basic design be improved to provide adequate flow rates at 
the required pressure and that adequate corrosion-resistant quick-connect fittings be provided. 
Although the Bibb system was not required in Sealab II, it is felt that it provides a required 
safety feature which should definitely be included in all future Sealab designs. 

Gas-Sampling System — The gas-sampling system performed its intended function and 
certainly should be included in any future designs. However, every effort should be made to 
obtain equipment for atmosphere analysis inside Sealab. It would also seem desirable to pro- 
vide the capability of detecting and monitoring the long-term buildup of trace contaminants 
which may create a safety hazard as test runs become longer in duration. 

Arawak System — It is recommended that sufficient lead time be allowed for satisfactory 
development of future Arawak systems. More efficient compressors and vacuum pumps are 
essential, but reduced noise levels are equally important. Hoses, vests, and regulators should 
be evaluated and tested to assure compatibility with diver's requirements. The installation of 
Arawak systems in Sealabs should also be designed to eliminate or reduce the noise level. 

Plumbing and Sanitary System — The discharge lines for the sanitary drains must be non- 
buoyant when filled with air or gas to prevent "trapping." The salt-water intake for the water 
closet should be extended downward to a point below the water level in the entrance trunk, to 
prevent atmosphere loss. A water closet with a larger flushing pump should be installed. 

Since the shower tubs were not utilized, they should be removed, and one shower should 
be eliminated to provide additional space in the entry. 

Provisions are necessary for increased water-supply capacity. The 50-gallon-per-man- 
day supply used for Sealab II was adequate but probably should be doubled for colder runs, 
where hot water may be used to restore or maintain the body heat of the divers. 



334 ENGINEERING EVALUATION 

Communication System — Inasmuch as adequate and reliable communications between 
Sealab occupants and surface-control personnel are of critical importance, the communication 
system deserves special attention. It is recommended that a complete study be made of the 
communication problems involved in a Sealab-type operation and that the special equipment 
required be developed. It is recommended that a helium-speech modifier be developed that 
would operate as an intercom set. Headphones could also be provided for secure communication. 

The electrowriter should be retained, since it has performed satisfactorily in the past and 
provides a good communication link. In view of the ink- splattering problem experienced in 
Sealab II, it is recommended that this problem be investigated and corrected. 

It is recommended that the entertainment TV and FM facilities be retained. It would be 
desirable to have individual speakers at each berth in the sleeping quarters in place of the one 
central speaker. 

Data Recording System — It is recommended that in future Sealab operations, required data 
be recorded remotely on the support vessel or on shore. This provision would ensure more 
complete data records and would relieve the subjects of the task of recording data or servicing 
recorders. Remote recording would also permit the use of standard off-the-shelf equipment. 
A separate cable should be provided in the umbilical cord for data-recording circuits. The 
following is a recommended list of data that should be recorded for engineering evaluation of 
the next Sealab operation. 

1. Electrical power (watts) 

2. Voltage 

3. Current 

4. Equipment power consumption 

5. Interior hull temperature 

6. Exterior hull temperature 

7. External water temperature 

8. Interior atmospheric temperature 

9. Interior atmospheric humidity 

10. Equipment operation time 

11. Equipment temperature 

12. Simultaneous audible and unscrambled helium speech 

13. Oxygen makeup 

14. Flow in various air ducts 

15. Water usage 

16. Remote readout of all sensing and control devices 

Equipment 

Refrigerator- Freezer — Refrigerator -freezer facilities must be designed and developed 
specifically for use in the Sealab environment. Commercially available equipments do not have 
the required refrigeration capacity, insulation systems, or control systems. Consideration 
must be given to the fact that the thermal efficiency of ordinary insulations will be reduced by 
an average factor of four. The atmosphere in Sealab is six times as conductive as air and has 
a much higher specific heat. The frequency of door openings is considerably greater than in 
normal use. The storage capacity must be increased by a factor of at least three in order to 
provide adequate storage. A chest type should be considered as a means of reducing heat 
losses when the doors are opened, and circulating fans which tend to blow out the cold atmos- 
phere should be eliminated. 



ENGINEERING EVALUATION 335 

Since the major use of the refrigerator in Sealab II was for cooling fruit and vegetable 
juices, it seems that a juice-can vending machine similar in operation to commercial machines 
might be advantageous. 

Cooking Equipment — Although the cooking equipment installed in Sealab II generally per- 
formed its intended functions, it is not considered to be the ideal arrangement. Certain safety 
hazards are presented in cooking in a closed atmosphere which are not normally considered in 
conventional situations. Also, since the pressure in the Sealab environment may be as high as 
18 atmospheres (600 ft), cooking times are considerably less than normal and boiling points 
are much higher. The boiling point of water in Sealab II was approximately 330° F and at 20 
atmospheres, 281 psia, water boils at 411°F. Considerable care must be exercised to mini- 
mize the introduction of hydrocarbons and other toxic vapors produced in uncontrolled cooking. 

In view of the above considerations, it is believed that the best methods for cooking in the 
Sealab environment are a microwave oven or an infra-red oven with a filtering system capable 
of removing all atmospheric contaminants produced. Water should be heated only in a closed 
container with precise temperature control to reduce evaporation and the possibility of severe 
burns. If a bread toaster is considered desirable, it must be designed to provide the required 
heating-element temperature (possibly by increased voltage) in the Sealab atmosphere. The 
toaster also should be adequately "filtered" to control atmospheric contaminants. 

Water Heater — Since the water heater in Sealab II seemed to be no more than adequate, an 
increased hot-water capacity will be required for deeper and colder runs. The required hot- 
water capacity for use inside Sealab could probably be provided with the existing heat input by 
increasing the storage capacity to 100 gallons and installing additional insulation. However, if 
hot water is utilized for heating or warming divers outside Sealab, additional water-heating 
capacity will be required. 

ACKNOWLEDGMENTS 

The authors wish to express their appreciation and gratitude to all who have contributed 
in the preparation of this report, and especially to Lawrence B. Taylor, Berry L. Cannon, 
Wallace T. Jenkins, and P. A. Wells, MNCA. 



Appendix A 
ENGINEERING AND ENVIRONMENTAL DATA-SEALAB II 

One of the important elements of the Sealab II operation was the recording of engineering 
and environmental data. Even though the data- re cording system used in Sealab II was simple 
and possessed some shortcomings, much useful data was obtained. 

The objective of this appendix is to present the reduced data in tabular and graphic form 
and discuss briefly how the raw data was obtained and reduced. 

The data were manually recorded by the Sealab personnel on preprinted forms and, in the 
case of water usage, by shore personnel. The major shortcoming was the failure of the Sealab 
personnel to record the data at regular intervals. The data recorded while the Sealab was 
manned by Team 1 was more complete than the recorded data of the second and third teams. 
Since the data recorded each day covered periods of time ranging from eight to 24 hours, all 
equipment running time was reduced to a common base for better comparison by reducing the 
running time for the recording period to percent of time operating. The graphs were prepared 
from the data recorded by Team 1 and are considered to be representative of the other two teams. 

During the period manned by Team 3 the power usage was recorded only four times. The 
peak-power requirement occurred during this period. However, in view of limited data it ap- 
pears that an error could have been made in reading the watthour meter, and that a peak-power 
requirement of this magnitude did not occur. The equipment-running-time meters do not indi- 
cate any unusually heavy electrical loads during this period. 



336 



ENGINEERING EVALUATION 



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a,s 



338 



ENGINEERING EVALUATION 



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0. rt 
« Q 



ENGINEERING EVALUATION 



339 



Table A4 
SEALAB II ENGINEERING AND ENVIRONMENTAL DATA 



1500 28 Aug 


through 2000 9 Oct 1965 


Item 


Units 


Average for Total Time 


Total Elapse Time 


Hr 


1013 


Electrical Power 


KW 


21 


Temp., Transformer 


°F 


74.8 


Baseboard Htg., Fwd 




3.9 


Baseboard Htg., Amid 




17.3 


Baseboard Htg., Aft 




2.1 


Water Heater 




29.8 


Deck Heating 


(U 


98.6 


D/H Machine Fwd 


s 


99.6 


D/H Machine Aft, Port 




99.5 


D/H Machine Aft, Stbd 
Refrigerator 


u 


98.9 
51.9 


Freezer 


Ph 


62.0 


Rad. Htr. No. 1 




6.7 


Rad. Htr. No. 2 




2.2 


Rad. Htr. No. 3 




49.0 


Rad. Htr. No. 4 




35.3 


Temp., Berthing 


°F 


87.0 


Temp., Galley 


°F 


86.0 


Temp., Lab 


°F 


88.9 


Temp., Entry 


°F 


90.5 


Temp., Refrigerator 


°F 


44.8 


Temp., Freezer 


"F 


37.5 


Humidity, Berthing 


%RH 


71.2 


Humidity, Galley 


%RH 


75.4 


Humidity, Lab 


%RH 


69.8 


Temperature, Habitat 


°F 


87.3 


Humidity, Habitat 


%RH 


72.1 



340 



ENGINEERING EVALUATION 




10 



20 25 

DAY NUMBER 



Fig. Al. Sealab II average daily electrical load 



1000 



400 — 




6 8 10 

DAY NUMBER 



Fig. A2. Sealab 11 average daily ■water consumption (Team 1) 



^ Q 80 — 

2 u 
u > 



J \ L 



TEMPERATURE 




J \ \ \ L 



I I I L 



6 S 10 

DAY NUMBER 



16 



Fig. A3. Sealab 11 average daily temperature and 
relative humidity in laboratory area (Team 1) 



ENGINEERING EVALUATION 



341 



- £ 90 



1- 9 80 



60 




J I I L 



DAY NUMBER 



Fig. A4. Sealab II average daily temperature 
and relative humidity in galley area (Team 1) 




DAY NUMBER 



Fig. A5. Sealab 11 average daily temperature 
and relative humidity in berthing area (Team 1) 



— 


A TEAM 1 
■ TEAM 2 
• TEAM 3 

1 1 1 1 1 1 


1 





2 4 6 8 10 12 


14 16 



DAY NUMBER 



Fig. A6. Sealab II average daily temperature 
of laboratory area for each team 



342 



ENGINEERING EVALUATION 



" 80 



o 70 

5 



▲ TEAM I 
■ TEAM 2 
• TEAM 3 




I I I I I I It I I I I 



J L 



6 B 10 

DAY NUMBER 



Fig. A7. Sealab II average daily relative humidity 
of laboratory area for each team 



100 



_ o 90 



1- Q 




• ELECTRICAL LOAD 

■ TEMPERATURE 

▲ RELATIVE HUMIDITY 



DAY NUMBER 



Fig. A8. Sealab II average daily temperature, relative humidity 
and electrical load in laboratory area (Team 1) 



Q 80 



S 5 



uj > 

I- H 70 



< 
- * 22 



< 

O 20 



161 

0000 




• ELECTRICAL LOAD 

■ TEMPERATURE 

A RELATIVE HUMIDITY 



0400 



0800 1200 1600 

TIME OF DAY IN 24 HOUR TIME 



Fig. A9. Sealab 11 temperature, relative humidity, and 
electrical load in laboratory area for a typical day 



ENGINEERING EVALUATION 343 

Appendix B 
HEAT-LOSS CALCULATIONS-SEALAB II 

COEFFICIENTS OF THERMAL CONDUCTIVITY 

K(Btu/hr-ft-°F) 

Steel (1% C) 25 

Corkboard 0.025 

Concrete 0.47-0.81, 0.64 (avg.) 
Air 0.015 

Helium 0.090 

Plexiglas 0.120 

HEAT-TRANSFER AREAS OF SEALAB II 

Two inches of cork insulation, sides and ends. 

Total side area = 2 [(7.5) (51.5)] = 772 ft^ 
Total end area = 311 - 85 = 226 ft ^ 
Total area, 2 in. cork = 998 ft " 

One inch cork insulation, overhead. 

A^ = 10 X 55.25 = 552 ft^ 
Concrete deck (one foot average thickness). 

Ad = 376 ft^ 
Port areas (Plexiglas, 1 in. thick). 
"77X 2^ 



Ap = 11 



= 34 ft-^ 



4 

Uninsulated Hull Areas. 

Entry area (below deck) = 73 ft^ 

Surface Access Hatch = 5 ft^ 

Emergency Exit Hatch = 5 ft^ 

A, = 83 ft^ 



HEAT LOSS FROM SEALAB II 

One of the major problems in determining the heat loss in Sealab II is the effect the helium 
atmosphere has on the insulation. It has been found previously that helium permeates most 
materials. Since helium is six times as conductive as air, this seriously affects the thermal 
conductivity of the insulation. 

It is known that if the gas within an insulating material is replaced by another gas having a 
different conductivity, the conductivity of the insulation will be changed by an amount very nearly 
equal to the difference in conductivity of the two gases. 



344 ENGINEERING EVALUATION 

The thermal conductivity of corkboard in a standard air atmosphere is 

K^ = 0.025 Btu/hr-ft-°F, 
and 

Kheuu. -K,,, =0.09-0.015 = 0.075. 
Then the new K,, would be 

Ke = 0.025 + 0.075 = 0.10 Btu/hr-ft-°F. 

The most difficult quantity to determine in any heat-transfer problem is the film coeffi- 
cient of the filir next to the insulating material. This determines the heat transferred by natu- 
ral convection. The simplest approach to solve for this quantity is by the following method. 

Consider a wall maintained at a constant temperature t„, coated with a layer of insulating 
material of a thickness x and of thermal conductivity K. The outside of the insulation is in 
contact with the atmosphere at temperature tg. Heat is transferred by conduction through the 
insulation and by natural convection through the atmosphere. In the steady state, the rate at 
which heat is conducted through a unit area of the insulation material is equal to the rate at 
which it is supplied to the air by convection, or 

where t is the temperature of the outside surface of the insulation. Besides K and x, t„ and 
tg are known. Since h varies as the fourth root of t - tg, the simplest way to solve for t is 
by trial and error. Thus, assuming t to be any arbitrary value, h is calculated and then mul- 
tiplied by t - tg. The value of (K/x) (t„ - t) is then calculated and compared with h(t - ta). 
If these quantities are not equal, another value of t is chosen, and so on until the equation is 
satisfied. To apply this to the present problem: 

^(t-t^) = h2(t3-t) t„ = 48° 

t. = 88° 
0.10 Btu/hr-ft-°F x 12 in./ft 







2 in 


• 


0.6 (t 


-48) 


= h2 


(88 - t) 


h2 = 


(ta- 


5)0.25 


= (88 - t)°-^' 


Assume 








t = 


85° 






h, = 


(88 - 


85)°- 


2^ = 1.316 


0.6(85 - 48) = 1 


.316(88 - 85) 


22.2 = 


3.95 




Assume 








t = 


70° 






h, = 


(88 - 


70)°- 


25 



(t - 48) = hi (88 - t) 

(corkboard) 



Xj = 2 in. 



Xj = 1 in. 
(corkboard) 



0.6(70 - 48) = 2.05(88 - 70) 
13.2 = 36.9 



ENGINEERING EVALUATION 345 

Assume 

t = 75° 
hj = (88 - 75)°" = 1.9 

0.6 (75 - 48) = 1.9(88 - 75) 
16.3 = 24.7 

Assume 

t = 80° 
hj = (88 - 80)°" = 1.68 

0.6(80 - 48) = 1.68(88 - 80) 
19.2 = 13.4 

Assume 

T = 78° 
ho = (88 - 78)°" = 1.78 

0.6(78 - 48) = 1.78(88 - 78) 
18 = 17.8 

Therefore a good value for hj (2 in. corkboard) is 

h. = 1.79 Btu/hr-ft^-°F. 
For 1 in. of insulation is 

0.10 X 12 ,, ,„, , ,„o ,, 



1 ' 


,1- " ^' 


3; - 


llj ^oo - 


1.2 (t - 48) 


= h 


(88 


-t) 


Assume 








t = 75° 








h2 = (88 - 


75)°- 


25 


1.9 


1.2(75 - 48) = 


1.9(88 - 75) 


32.4 = 


24.7 






Assume 








t = 73° 








Hj = (88 - 


■ 73)° 


.25 


1.97 



1.2(73 - 48) = 1.97(88 - 73) 
30 = 29.6 

Therefore a good value for hj (1 in. corkboard) is 

hi = 1.98 Btu/hr-ft2-°F. 



346 ENGINEERING EVALUATION 

For the sides and ends (2 in. corkboard) 
1 1 1 



U = 



1 1 0.559+1.67 2.23 

+ 



1.79 0.6 
U = 0.448 Btu/hr-ft--°F 
Area of sides and ends (less port area) = 998 - 34 = 964 ft". The heat loss is 
Q = UA At = 0.443 X 964 x 40 

Qsides6.ends = 17,300 Btl,/hr. 

For the top (1 in. corkboard) 

= 0.746 Btu/hr-ft^-^F 



^ - 1 1 

1.98 ' 1.2 


0.505 + 


0.835 


The heat loss is 






Q = 0.746 X 


552 X 40 




Qt„p = 16,500 Btu/hr. 




For the ports (1 in. 


Plexiglas) 




Film coefficient, hp 






K„ 







-^(t-tj = hp(t3 -t) Ap = 34ft2 

p 



0.12 X 12 



^ VI ■ -^u) - 


"pV 


1.44(t - 48) = hp(88 


-t) 


hp = (88 - t) 




Assume 




t = 71° 




K /QD _. r7iN0.2S 





lip v,w.J . i/ 

2.88(71 - 48) = (88 - 71) 2.03 
33.1 = 34.5 



Therefore 



hp = 2.02 



Then 



^p ~ _J_ J_ ~ 0.459 + 0.694 1.19 °-^'*° 
2.02 ■^ 1.44 



Kp = 0.12 Btu/hr-ft-°F 
t. = 48°F 
t, = 88°F 



Xp = 1 in. 



ENGINEERING EVALUATION 



347 



The heat loss is 

Q = 0.840 X 34 X 40 



Qp = 1,140 Btu/hr. 



Concrete Deck 

Since radiant heating cables were imbedded in the concrete deck, two inches below the 
surface, it is logical to assume that this portion of the concrete would be maintained at a higher 
temperature than the Sealab atmosphere. There a t^ of 95° F was selected for use in this cal- 
culation. Film coefficients are neglected. 



Qd = K^ X Ae X At = 0.64 x 376 x 46 
Qd = 11,100 Btu/hr. 



Uninsulated Hull Areas (Steel) 
Film coefficient, hj 



A^ = 376 ft-^ 



Kj = 0.64 Btu/hr -ft-°F 
t. = 48°F 



tad = 94°F 



Xd = 1 ft (avg) 



— (t-tj = h3(t3-t) 



25 X 12 



(t - 48) = h^ (88 - t) 



400 (t - 48) = h (88 - t) 
h, = (88 - t)°" 
Then if 

t = 48.25° 
h^ = (88 - 48.25°)°" = 2.5 
and substituting for t and h^ 

4(48.25 - 48) = 2.5(88 - 48.25) 
100 = 99.4. 
Therefore 
h, = 2.5 



A, = 376 ft 2 

k3 = 25 Btu/hr-ft-°F 

K = 48°F 

ta = 88°F 

X , = 1 in. 



U. 



J_ ^ _J_ J^ 0.44 + 0.0025 
h "^ k 2.5 "^ 400 

s s 



U, = 2.49 Btu/hr-ft2-°F 



348 ENGINEERING EVALUATION 

Q, = U, X A3 X At = 2.49 X 83 X 40 
Q3 = 8,300 Btu/hr. 

TOTAL HEAT LOSS 

Q total = Q sides & ends + Qfop + Qp + Qd + Qs 

= 17,300 + 16,500 + 1,140 + 11,100 + 8,300 
= 54,340 Btu/hr. 

Appendix C 
SPECIFIC -HEAT RELATIONS 

Constant-pressure specific heat (Cp) is defined as that quantity of heat required to cause 
an increase of one degree in the temperature of a unit quantity of material under constant 
pressure conditions [Btu/lb-°F]. For air at standard conditions, Cp is equal to 0.241 Btu/ 
lb-°F. 

The Sealab II environment consisted of 85 percent helium, 11 percent nitrogen, and 4 per- 
cent oxygen. The specific heat of this mixture of gases can be determined using the relation 

^ Cp^wi + Cp^wg + ... + Cp^w„ 

= 1.25(0.85) + 0.247(0.11) + 0.217(0.04) 

= 1.1 Btu/lb-°F. 

The operating pressure of Sealab n required seven times the amount of gas needed to fill 
it to standard atmospheric pressure. To remove a given quantity of heat from a unit volume of 
the gas mixture under Sealab n operating conditions would require 32 times the energy required 
to remove the same amount of heat from a unit volume of air at standard atmospheric pressure, 
i.e. 

Heat Capacity (SEALAB environment) 
Heat Capacity (Air at sea level) 

Cp (Specific heat of mix) Xp (Density of mix) = 1.1 x .141 



Cp (Specific heat of air) X p (Density of air) = .241 X .074 



= 8.6. 



Chapter 39 
OCEANOGRAPHIC INVESTIGATIONS 

W. H. Tolbert and G. B. Dowling 

U.S. Navy Mine Defense Laboratory 

Panama City, Florida 

INTRODUCTION 

Since the U. S. Navy Mine Defense Laboratory has had a long-standing interest and expe- 
rience in the application of diving for scientific purposes (1, 2, and 3), a program for conducting 
oceanographic studies from Sealab II was formulated. Development of this program was guided 
by the following general considerations. 

1. Conduct research which emphasized having the trained eye on the spot. 

2. Explore the feasibility of Sealab-type habitats as oceanographic platforms. 

3. Attempt to take advantage of the potentially longer bottom times at depths afforded by 
Sealab. 

4. Perform research in the area of physical oceanography with emphasis on those aspects 
which have potential usefulness for application to naval problems. 

The proposed program resulting from the foregoing considerations, after several modifica- 
tions, provided for both the general monitoring of undersea weather and more detailed stud- 
ies in a number of specific problem areas. In all, it was proposed to record and monitor four 
general environmental parameters and to investigate, in more detail, 15 specific problem areas. 

The writers were aware that there were a number of factors which might preclude the 
successful accomplishment of all the proposed efforts. Among these factors were: 

1. The program was deliberately designed to be overly ambitious, in order to insure max- 
imum utilization of bottom time; e.g., in the event that certain tasks were not possible even to 
attempt, there would still be sufficient work available. 

2. It was necessary to provide flexilility to allow for the inclusion of new research tasks 
which may be revealed only after gaining experience in the Sealab environment. 

3. An imdeter mined amount of time would have to be diverted from the oceanographic pro- 
gram for participation in humanfactor studies, supply, housekeeping, and watchstanding. 

In the sections that follow there will be detailed discussion of the final planned program, 
including those results and conclusions that are presently available, and/or a discussion, where 
necessary, of reasons why certain parts of the program were not successfully accomplished. 

Following this there will be a general discussion of conclusions and recommendations 
which hopefully will aid in better planning and execution of future Sealab investigations. 



349 



350 



OCEANOGRAPHIC INVESTIGATIONS 



DISCUSSION OF OCEANOGRAPHIC PROGRAM AND RESULTS 

General Environmental Parameters 

In order to provide general background data commonly needed in support of many phases 
of the Sealab effort, a number of environmental sensors were maintained sample as often as 
possible those factors which influences the under seaweather. These sensors, which included 
both instrumentation provided by MDL and Scripps Institution of Oceanography, were located 
as shown by Fig. 130. Wherever possible automatic sampling and recording instrumentation 
were employed. These data were supplemented by measurements obtained by divers and ob- 
servations from within Sealab. Listed below are those parameters which were monitored along 
with a brief description of the instrumentation, methods employed and preliminary results. 
Only MDL instrumentation and results are described; the Scripps program will be discussed 
in Chapter 40. 




1. BENTHIC 

2. POWERHIVE 

3. WEATHER STATION 

4 MDL CURRENT METER NO. I AND THERMOGRAPH NO. I 

5. MDL CURRENT METER NO. 2 

6. VISIBILITY RANGE 

7. SIO WATER CLARITY METER 



Fig. 130. Location of Environmental sensors 
and visibility range in sealab II area 



Temperature — The thermal characteristics of the water adjacent to Sealab were measured 
by recording thermographs, a bathythermograph (BT), and a mercury stem thermometer. 

Three recording thermographs made by Braincon Corporation were used to record changes 
in water temperatures as a function of time. These instruments are self-contained units which 
record on 70-mm photographic film the position of the mercury column of a glass thermometer 
with an accuracy of ±0.25 °C (0.45 °F). The film -advance mechanisms were adjusted to provide 
a sampling interval of ten minutes. Two of the units were attached to Sealab, one was positioned 
in the shark cage at the bottom, and the other was located on the catwalk some 6.1 meters (20 ft) 
above the bottom. The third unit was positioned on the bottom at MPL current meter 1 some 
27.4 meters (90 ft) from Sealab. The two units attached to Sealab were recovered, and the data 
are presently being processed. Attempts to locate the third unit, which had been attached to a 



OCEANOGRAPHIC INVESTIGATIONS 



351 



stake near the current meter, were unsuccessful. A concerted search of the nearby area was 
made, but the instrument was not found. The failure to recover this instrument resulted in a 
serious loss of valuable data, since it contained the only data made away from Sealab suitable 
for correlating with thermograph data made at Sealab. 

Temperature variation as a function of depth were provided by a standard shallow -water 
bathythermograph (BT). During occupancy of Sealab by Teams 1 and 3, the writers made BY 
lowerings from the surface-support vessel. During Team 2's occupancy the writers obtained 
BT data by operating the instrument in an "upside-down" manner from the bottom. This was 
done by attaching a flotation bag to the BT, which provided sufficient buoyancy to raise it to the 
surface. Also attached was a nylon line, which with the aid of a small hand winch, allowed just 
as easily as from the surface. Additionally, BT's taken from the bottom yielded somewhat bet- 
ter traces in general than those taken from the surface. This was due to the fact that "upside- 
down BT's" did not exhibit the scratches typical of BT's taken from the surface. Fig. 131 shows 
a comparison of BT's taken from the bottom and surface. In all, 45 BT observations were made, 
six of which were made from Sealab. 





II Up' 



Wi 


" iiii*^iifliH^^^^^^^^^^^ 




^■fiHHKdlR^^^^^^H 




s 


■ 

*_.____ __ 



Fig. 131. A comparison of surface and 
bottom-taken bathythermographs. Upper 
slide was nnade from the Surface Support 
Vessel; lower slide was taken from Sea- 
lab II 



During Sealab's occupancy, the surface temperature varied from 18° to 21°C (65 to 70-F) 
with temperatures in the range of 19° to 21 °C (67° to 69 °F) predominating. Bottom tempera- 
tures varied from 11° to 14°C(52 to 58°F) with temperatures in the range of 12° to 13°C (53° 



352 



OCEANOGRAPHIC INVESTIGATIONS 



to 55° F) predominating. The variation of the temperature with depth indicated that generally a 
two-layered water structure was present. The region separating the two water masses, i.e., 
thermocline, varied both in thickness and depth; however, the maximum depth of the bottom of 
the thermocline never exceeded 46 m (150 ft). The thermal gradient within 15 m (50 ft) of the 
bottom was very weak, never exceeding 1°F variation over this depth interval. 

In order to monitor the outside water temperature from within Sealab, a mercury stem 
thermometer was positioned so it could be easily read from a port within the lab area (Fig. 
132). Readings were made by the watch crew and were entered in the Sealab log periodically. 
This thermometer was an immersion mercury stem thermometer in a protective housing. 
These thermometers, normally used at the surface, may be affected by the pressure at 61 m 
(200 ft), and a calibration check will be made to determine the depth- correction factor. 




Fig. 132. Aquanaut Dowling checks the outside water temperature from 
a stem thermometer hanging outside the Sealab II viewing port 



Currents— Current speed and direction in the vicinity of Sealab were monitored by two 
sell- contained recording type Geodyne current meters, Model A- 100. These were located ap- 
proximately 27 m (90 ft) away from Sealab (Fig. 130). The data from these instruments were 
recorded digitally on film at a 15-min sampling interval and are presently being processed 
for future analysis. 

During Team 2's occupancy of Sealab, estimates of current speed were made by the writ- 
ers while diving by timing the drift of particulate matter over known distances. Maximum 
current- speed observed by this technique was approximately 5 cm/sec (0.1 knot). 

Water Clarity — Measurements of water clarity were made with an S.I.O. water clarity 
meter (4) which was lowered from the surface to within approximately 3 m (10 ft) from the 
bottom (Fig. 130). This instrument recorded both the beam- attenuation coefficient and the 



OCEANCXJRAPHIC INVESTIGATIONS 353 

scalar irradiance at depth. Data obtained from this instrument are being analyzed for corre- 
lation with water- visibility measurements taken by divers. 

Tides— Changes in the water level above Sealab were monitored by (a) a Hytech Model 
4000 water-level monitor and (b) a Braincon temperature-Depth recorder, Type 148. The 
Hytech monitor utilizes a precision Mechmetal bellows to alter the tension in a vibrating be- 
ryllium copper wire to measure changes in hydrostatic pressure. The output of this instru- 
ment was recorded on a Rustrak recorder located in Sealab. This instrument was in operation 
during Team 2's occupancy. In the Braincon depth recorder the movement of a helical Bourdon 
tube is contact printed on 70- mm photographic film. This instrument was attached to Sealab; 
the transducer of the Hytech unit was pyositioned some 15 m (50 ft) from Sealab. The location 
of both of these instruments is shown by Fig. 130. The Braincon unit was in operation from 
Sept. 6 to Oct. 8. The records from both of these units, after corrections for changes in baro- 
metric pressure, will be correlated with records from a Coast and Geodetic Survey tide gage 
located at the end of Scripps pier. The film record from the Braincon unit is presently being 
processed. The maximum tide range recorded by the Hytech unit was approximately 2.3 m 
7-1/2 ft), which was in good agreement with the 2.4 m (7.8 ft) maximum predicted tide range 
for this period. 

Specific Problem Areas 

Of the 15 specific research tasks planned, useful results were obtained from eight. In the 
interest of completeness, however, aU of the planned tasks will be discussed giving either pre- 
liminary results or reasons why a task was not completed or successful. Also included in this 
discussion are several problem areas which came to light during the writer's occupancy of 
Sealab. 

Horizontal Visibility measurements by Swimmers — Although considerable progress has 
been made in recent years concerning the visibility of objects by swimmers, there is a paucity 
of adequately controlled experimental data with which to verify existing prediction theories. 
Sealab H offered the opportunity to obtain needed data at depths sufficient to insure uniformity 
of the radiance distribution, for a time interval of sufficient duration to obtain a wide range of 
light levels and transparency, and in water of excellent spatial uniformity. In order to take 
advantage of this opportunity, the S.I.O. water- clarity meter (4) was used to monitor the optical 
characteristics of the near-bottom seawater, while swimmer measurements were made at a 
specially constructed horizontal visibility range. This range, located about 21 m (70 ft) from 
Sealab (Fig. 130), consisted of four visual targets arranged as shown by Fig. 133. The targets 
consisted of a white square, a black circular disc, a white cross, and a yellow triangle. The 
three angular targets were of equal area (906 sq cm), 140 sq in), while the black disk was 
somewhat smaller (707 sq cm) (109 sq in.). The apparent reflectances (R^,) of the submerged 
targets as measured by the S. I. O. visibility laboratory were: white square and white cross 
0.875; black disk 0.506. The origin of a 15-m (50 ft) measuring tape was attached to the sup- 
port stake of the black disk. The procedure for obtaining visibility measurements was as fol- 
lows. Two swimmers, starting at the end of the measuring tape, swimming horizontally at or 
slightly below the target level slowly and carefully approached the targets until some target 
was first detected. The swimmers' position along the tape was then recorded as the range of 
detection. The approach then continued in this manner until the detection range of each target 
was recorded. In like manner the range at which the shape of each target could be discerned 
was recorded. Since the measurii^ tape was not in the center of the range, both swimmers 
swam to the right of the tape in order to minimize error due to the angular spread of the tar- 
get array. Resulting from each visibility run were two sets (detection and identification) of 
four ranges for each swimmer. A total of 20 visibility runs was made. Extreme detection 
ranges varied from a minimum of 2.4 m (8 ft) to a maximum of 9.1 m (30 ft). Extreme iden- 
tification ranges varied from 1.5 m (5 ft) to 8.5 m (28 ft). A preliminary inspection of the data 
has shown that the black disk even though smaller in size, was always the first target to be 
detected and identified. A detailed analysis of these data is being conducted, and an attempt 
will be made to use these results, in conjunction with the water-clarity-meter data, to verify 
the Duntley-Preisendorfer underwater visibility range prediction theory. 



354 



OCEANOGRAPHIC INVESTIGATIONS 



WHITE BLACK WHITE YELLOW 
SQUARE DISK CROSS TRIANGLE 




Fig. 133. Sealab II form/color visibility range 



Bioluminescence— Bioluminescence, the production of light by living organisms, is a com- 
mon occurrence in the marine environment. Since the advent of nighttime naval operations, 
bioluminescence has become a problem of military significance and has received the attention 
of a number of investigators (5, 6). Actual reports of bioluminescence however are few, and 
for the most part consist of sightings by mariners of only exceptionally brilliant displays, of- 
fering little in the way of quantitative or qualitative information. In 1963, Seliger, Fastie, 
Taylor, and McElroy (7) developed a portable light-baffled underwater photometer capable of 
measuring the bioluminescent intensities of planktonic organisms while eliminating interference 
from ambient light. Several of these meters were made for the U.S. Navy Oceanographic Of- 
fice, and the writers were fortunate to obtain one of these for use in Sealab 11. In operation, 
water (with its plankton population) is drawn into a light-tight impeller housing and churned 
rapidly, stimulating luminescent forms into light production. The output of the luminescent 
organisms is measured by an RCA 1P21 photomultiplier tube. Measurement of the phototube 
current is made by a transistorized dc amplifier which is included in the phototube housing. 
Response of the amplifier is such that the integrated signal can be recorded on a Rustrak re- 
corder. During Team 2's occupancy of Sealab, the sea unit of this instrument was attached to 
the conning tower, and a number of night runs were made to measure the bioluminescent back- 
ground level. Measurements made after Sept. 15 revealed that the level of bioluminescence 
was less than the threshold detection capability of the instrument. On Sept. 15 the biolum- 
inescent level was sufficient to cause half-scale deflection on the instrument's most sensi- 
tive range. The effective input light level corresponding to this deflection will be determined 
by calibration data for the instrument. 



The measurement of bioluminescent levels made with the meter correlates quite well 
with diver observations of this phenomenon. On all night dives made between Sept. 12-15 a 
noticeable amount of bioluminescence in the water was reported. After Sept. 15, the amount 
of bioluminescence suspended in the water appeared to be much less. One interesting obser- 
vation concerning the occurrence of this phenomenon at these depths is that the most intense 
displays were restricted to a very narrow (less than 1 in.) region above any exposed surface. 
Thus by generating a current a diver could see in detail the surface of a rock at the edge of 
the canyon or small surface protuberances in the darkened exterior areas of Sealab. Since 
the organisms responsible for these displays remained near or attached to the surface of these 
objects, they could not be pumped in and detected by the bioluminescencence meter. Copepods 
and euphasids appeared to be the primary producers of bioluminescence at these depths. 



OCEANOGRAPHIC INVESTIGATIONS 355 

Sonar Conditions— An important problem from the point of view of naval applications is 
that of short-range acoustic transmission variability as related to the oceanographic environ- 
ment. In order to study this problem from Sealab II, tape recordings were made of sonar re- 
turn, from several fixed targets, for later correlation with environmental parameters obtained 
from both the NAVMINDEFLAB instrumentation and the SIO weather station. The sonar 
chosen for this task was the AN/PQS-IB, a diver-held, continuous- wave, frequency- modulated 
(55 to 85 kc) unit that is, and will be, commonly used in Sealab type operations. Sonar runs 
were made by pointing the sonar at two preselected, fixed, strong targets which were reliably 
reidentifiable. By carefully bracing himself against Sealab, the operator could hold the sonar 
steadily on each target for three to five minutes, during which time a tape recording was made 
of the sonar's audio output. After this time, the sonar was held pointed upward at the surface 
and a three-minute recording made. In all, six such runs were made over three days, cover- 
ing times of day from 1000 to 2145. There were noticeable differences in both target and sur- 
face signals from day to day and from morning to night. The tape recordings will be analyzed 
for relative energy content as a function of frequency, and correlated with oceanographic data. 
Although the analysis technique will obviate the need for knowing absolute acoustic levels, care 
was taken during data collection to insure that sonar and tape-recorder gains were constant 
and/or known, so that comparison of actual signal levels can be made. 

General Bottom Conditions and Settlement of Sealab II — A general survey of bottom type 
and topography was made in the immediate vicinity of Sealab II. Sediment in this area was a 
dark gray, micaceous, very fine silty sand with few marine shells and a trace of clay. The 
upper one or two centimeters of sediment contained a large proportion of relatively loose fine 
silt which was easily disturbed and placed in suspension, with generally a drastic loss of visi- 
bility for divers. Analysis of a surficial sediment sample obtained in the vicinity of Sealab II 
yielded 81 percent sand, 19 percent silts and clays, with a median diameter of 0.095 mm. Lab- 
oratory tests of soil-engineering properties of this sample were made giving the following 
results: angle of internal friction, 22 degrees; cohesion, 976 kg per square meter (200 lb per 
sq ft); unit buoyant weight, 833 kg per cubic meter (52 lb per cu ft). From these data it was 
calculated that Sealab should have a safety factor of about three against footing settlement of 
as much as 61 cm (two feet). 

At the Sealab II site the bottom generally sloped up to the southeast at about 8 degrees. 
Small-scale bottom relief was of the order of one to four inches and was of irregular appear- 
ance, consisting largely of mounds and depressions of biological origin. Occasionally seen 
were scattered debris consisting mostly of remains of sea grasses and kelp from shallower 
depths; also seen were fragments of shells and echinoderms. Within about 15 m (50 ft) of 
Sealab, the bottom appearance had been drastically modified and scarred by the presence of 
Sealab and divers; many of these scars persisted throughout the duration of the experiment. 

Measurements of the angles of roll and pitch made inside Sealab with a plumb bob indicated 
a port list of 6.54 degrees and a bow-up pitch of 5.96 degrees. Similar measurements made 
during Team I occupancy indicated that these angles had not appreciably changed over a period 
of three weeks. It was thus apparent that Sealab was stably sitting at a lesser slope than that 
of the outside bottom, implying a differential footing settlement at its four corners. In order 
to check this, the writers made careful measurements of footing settlement; the results were 
as follows (data are with respect to bottom of main footing I-beams to which spades were at- 
tached): starboard aft, 23.1 cm (9.1 in.); starboard fwd, 40.1 cm (15.8 in.); port aft, 23.3 cm 
(9.2 in.); port fwd, cm. Thus the starboard forward corner was dug in more than the others, 
while the after end settled evenly. These measurements were repeated after an interval of 
several days, yielding the same data; thus from these settlement data and from the inclination 
data one concludes that essentially all of the settlement occurred on impact or very shortly 
thereafter. 

General Observations of Near Bottom Underwater "Weather" and Biology — A number of 
general and somewhat unrelated observations of the undersea weather and the behavior of 
various marine organisms were made by the writers during Team 2's occupancy of Sealab, 
which, because of the uniqueness of the situation, should be documented. 

Porthole watching became the favorite pastime of the entire crew, and many hours were 
spent observing the antics of our outside neighbors. Although at 62.5 m (205 ft) the light level 



356 



OCEANOGRAPHIC INVESTIGATIONS 



was considerably reduced, there was a noticeable diurnal rhjrthm in the movement of fish. 
During the night the white croaker, Gengonemus lineatus , would typically crowd near the port 
holes, often occurring in such numbers as to completely obscure the port (Fig. 134). With the 
approach of dawn the croakers would leave the ports but could be seen swimming in large 
schools, all generally pointed in the same direction, several feet away. It appeared to the 
writers that the croakers were attracted to the ports to feed on the small crustaceans ( Eupha - 
usia sp) which gathered at the port holes during the night in great numbers. One curious note 
concerning the occurrence of these small organisms at the ports is that after the T. V. camera 
was placed outside the port window in the laboratory area, many would become trapped in the 
recessed area between the port window and the camera face plate. By morning this area would 
typically become completely filled with these organisms. After leaving Sealab the writers men- 
tioned this to the psychologists, who continually monitored the TV receivers and learned that 
they were completely unaware of the presence of these organisms; apparently TV reception 
suffered little. 




Fig. 134. White Croakers, Geneonemus Lineatus , crowd near the viewing 
port in the Sealab II laboratory area 



The small crustacean forms were also a favorite food of the squid, and quite often these 
strange animals could be seen actively feeding in the company of many types of fish and would 
thus themselves become food. Such a situation was witnessed by the writers who observed a 
calico rockfish (Sebatodes dalli) cautiously stalk a squid feeding outside a port in the labora- 
tory area. Very slowly and carefully the rockfish approached the squid until it was only about 
15 cm (6 in) from its prey. With a sudden movement the squid's head and tenacles were inside 
the fish's mouth. The squid then discharged its black ink, which was seen flowing from the 
sides of the mouth. Very quickly the fish released his hold on the squid and shaking his head, 
as if the ink was most distasteful, rapidly left the field of view. The squid, however, seemed 
to be totally unconcerned by his recent experience and remained near the port for several 
minutes, continuing his feeding activities. To the writers' knowledge, the ink discharge of 



OCEANOGRAPHIC INVESTIGATIONS 357 

squid has been considered to be primarily a smoke-screen defensive mechanism. From this 
observation, it thus appears that the discharge also serves as a taste deterrent. 

Over the short time interval the writers occupied Sealab, there was a noticeable change in 
the types and density of fish present. Sculpin, Scorpaena guttata, were always present, and 
several counts were made of their density on the bottom. In the area immediately adjacent to 
Sealab an average of 2 per 0.1 sq m (sq. ft) was observed. These fish decreased in numbers 
somewhat at a distance from Sealab. At approximately 15 m (50 ft) away an average of only 1 
per 0.1 sq m (sq ft) was observed. Through conversations with CDR Carpenter, the writers 
learned that these fish were not present during the early part of Team I's occupancy, but had 
moved in during the latter part of the first week. The white croakers were always present, 
but were most numerous during the first week of Team 2's occupancy. About the time the sea 
lions appeared on the scene, the number of croakers decreased sharply and it is possible that 
the desirability of croakers as food may have been in part responsible for this decrease. The 
sea lions were first observed on the night of Sept. 22. This first night they appeared to be 
somewhat cautious and were seen swimming only at a distance. By the next night, however, 
the sea lions had apparently decided that Sealab offered no threat and on several occasions they 
were seen hanging on the diving lights and looking in the ports. All of the fish in the immedi- 
ate vicinity could somehow sense the approach of a sea lion, and some 10 sec prior to the ap- 
pearance of a sea lion the fish would rapidly depart from the field of view. Only the sculpin, 
Scorpaena guttata, seemed to be unaffected by the sea lion's approach, and even though these 
fish made no attempt to escape, they were never taken by the sea lion. On the night of Sept. 
23 a marked change in water color was noted, the water changing from a predominantly green, 
typical of coastal waters, to an oceanic blue. Accompanying this change in water mass was 
the appearance of the northern anchovy, Engraulis mordax, which occurred in great numbers, 
becoming the predominant fish present. These fish were strongly attracted by the outside div- 
ing lights, and the protective screen of these lights often became completely filled with ancho- 
vies that had gilled themselves. These lights thus became a favorite feeding post for the sea 
lions, and on several occasions sea lions were seen feeding on the anchovies that had become 
gilled. By the night of the 25th of September, the water color had changed back to the typical 
green and most of the anchovies had departed. From conversations with CDR Carpenter, the 
writers learned that the anchovies had made a similar appearance during Team I's occupancy 
of Sealab; this appearance also coincided with the occurrence of oceanic blue water. A check 
of the predicted tides indicates that in both instances this change in water mass occurred dur- 
ing a period of maximum tide range. 

Underwater Surveying and Mapping 

A problem of major importance to both the Sealab oceanographic program and to other 
facets of the Sealab work was that of underwater surveying and mapping. Although, as de- 
scribed in what follows, useful partial solutions have been provided, the problem of accurately 
positioning, surveying, and mapping the location of underwater objects near Sealab remains as 
a significant problem yet to be fully solved. The prime reasons for this situation are, of course, 
that members of an underwater survey team are not only deprived of both aural and visual 
communication but also of many of the commonly used instruments, such as, e.g., transits. 
There is a pressing need to provide an vmderwater survey technique that is accurate, yet in- 
dependent of visual and audio links, and reasonably simple for use by divers. An approach 
toward solution of this problem as described below, devised primarily for oceanographic ap- 
plications, turned out to have usefulness in other areas. For example, it became apparent 
after Team 2 had entered Sealab that the magnetic heading of Sealab was not known with cer- 
tainty to within less than about ±20 degrees; we were able to reduce this uncertainty to about 
±5 degrees. To do this, two simple devices were used: a 61-cm (two-foot) diameter compass 
rose mounted on the bottom, and a 30.5-m (100 ft) steel-reinforced surveyor's tape in a reel 
specially designed for underwater use. The compass rose, which was made of plastic, was 
marked in one-degree increments and mounted on a heavy platform stake so that once set it 
did not rotate. In use, it was aligned by having a swimmer go out on a known preselected 
bearing by compass (to a distance such that his compass was not affected by Sealab or other 
metal objects) with a string attached to the center of the compass rose; after this the compass 
rose was adjusted so that the preselected bearing was under the string. In this manner the 
rose was aligned with respect to magnetic north to an accuracy matching that of the compass 



358 OCEANOGRAPHIC INVESTIGATIONS 

used, and problems of unknown effects due to nearby metal objects were avoided. Subsequently, 
any desired direction could be measured merely by stretching a string from the rose in the 
unknown direction and reading the bearing from the rose. By means of this technique the mag- 
netic heading of Sealab II on the bottom was found to be about 78 degrees. 

The surveyor's tape is a standard Lufkin tape refill #0506ME mounted in a plastic reel 
designed for simple and foolproof underwater operation. Use of the compass rose and tape 
together can provide range and bearing data, and two roses (separated by a known amount) or 
two tapes (from known positions) can provide triangulation data. The disadvantages of this 
technique are that (a) the divers are separated (and often out of sight of each other), but are 
connected by the tape or line so that hand signals may be used, and (b) the tape or line must be 
pulled straight and is susceptible to hanging on objects near its middle, causing possible un- 
known errors. Also, this procedure is cumbersome if ranges in excess of several hundred 
feet are involved. 

Another device which proved to be useful for this work was the NAVMINDEFLAB Divers 
Observation Board (1), which consists of a writing surface combined with built-in compass, 
depth gage, inclinometer, bubble level, and ruler and which has receptacles for pencil, 1.8-m 
(6-ft) folding rule, stem thermometer, and 7.6-m (25-ft) circling line. 

Ambient Noise Conditions 

Due to the presence of generators and other loud sound sources, it was realized from the 
outset that the true oceanographic ambient noise level could not be measured near Sealab II. 
However, for future design consideration, and for certain underwater audio experiments, there 
was the need to know acoustic levels, both outside and inside Sealab II. Records of ambient 
noise level were made by use of a NAVMINDEFLAB Sound Measuring Set, which provides the 
capability to record, on both analog strip chart and magnetic tape, sound levels in three filter 
bands to an accuracy of ±1 dba.* The hydrophone, positioned at the observer's station of the 
human-factors program acoustic range, was about 40 ft from the after port side of Sealab II. 
Recordings were made of (a) ambient noise outside Sealab II, (b) ambient noise inside Sealab II 
both with and without the Arawak pumps operating, (c) helium speech, and (d) calibration level 
signals from the sound -measuring set. The tape recordings will be further analyzed in narrower 
filter bands to obtain the spectral distribution of energy. Acoustic levels observed in the water 
were quite high, namely, of the order of 40 dba (with occasional peaks going to 55 dba) in the 
frequency range 400 cps to 30 kc. Analysis of sound levels inside Sealab II will be undertaken 
after obtaining calibration data on the microphone provided with the tape recorder. 

Surface Wave Measuring System 

A problem of potential importance to future Sealab type experiments for which there is 
no staging vessel at the surface is that of determining the surface-wave condition. Wave ef- 
fects directly observable at the bottom (e.g., pressure variations) yield information only about 
waves of length greater than roughly twice the water depth; hence a method for obtaining in- 
formation about the shorter, and usually more energetic, wind-generated waves is needed. A 
very simple, yet effective, approach toward solution of this problem was tried during Sealab 
II. The technique consists of floating at the surface a small buoy which effectively follows the 
surface motion; i.e., it rides up and down with the wind waves. This float is attached to a 
small, light, nylon-covered wire whose length is adjusted so that a small weight (approximately 
one pound) attached to the lower end is positioned about 4 or 5 ft above the bottom. Divers 
then observe and measure the up-and-down motion of this weight to obtain surface-wave height 
data. It proved to be very easy to position the origin of a meter stick at the lowest point of a 
wave cycle, i.e., at the trough, and then to observe the height on the meter stick of the highest 
point of motion, i.e., at the crest. In this manner it was feasible to use the standard method 
of measuring 30 waves and averaging the highest 10 to obtain the significant wave height. To 
make a measurement of significant wave height requires only about 5 to 10 minutes. It is 
realized that there is some error in this technique, since such a float-mass system does not 
exactly follow the surface waves; however, as long as the float remains above the surface, 
this error can never exceed the height of the float (about 15 in. in the trials described here), 



^'Reference: 1 dyne/cm^ 



OCEANOC^APHIC INVESTIGATIONS 



359 



and will in general be smaller. Also, considering the fact that needed accuracy is only about 
±1/2 ft, it is evident that the system described herein provides sufficient accuracy for most 
purposes. Once the float has been installed it can be left in place, except that when not being 
used it should be secured about 15 to 20 ft below the surface. 



INVESTIGATION OF THE EFFECTS OF THE SEALAB H ENVIRONMENT ON PLANTS 

To determine the effects of the Sealab environment on the germination, growth, and de- 
velopment of plants, an attempt was made to grow barley (avivat), marigolds (Spungold) and 
Alaskan peas during the submergence of Sealab II. This experiment was designed and directed 
by the Department of Plant Sciences, Texas A & M University; the writers potted and maintained 
the plants aboard Sealab, along with a log of their germination, growth, and development. The 
plant experiment consisted of two 12 -in. -square wooden trays, each containing 25 small pots 
filled with peatmoss, perlite and slow-release fertilizers (Fig. 135). The pots were planted 
with seed and placed in Sealab prior to germination. Each box initially contained 15 pots of 
barley and 10 pots of marigolds, while each pot was planted with two seeds. The Alaskan peas 
were not planted until the second week of Team 2's occupancy of Sealab, at which time ten pots 
of marigolds were removed and replaced with the peas. A bank of eight 50-w Sylvania rough 
service incandescent frosted bulbs located some 66 cm (26 in.) from the surface of the boxes 
provided light. A plexiglas filter 0.33 in. thick was positioned in front of the light source to 
protect the plants from excessive heat. The plants were watered as required and checked two 
to three times per week to record germination and growth. During the first week a heavy mold 
developed and completely covered the surface of the pots. Even though a fungicide was admin- 
istered two to three times per week, this mold persisted throughout the plant experiment and 
was, no doubt, an important factor in this experiment. 




Fig. 135. Sealab II plant experiment 



Of the plants tested, barley was the only plant that was able to withstand successfully the 
severe environment offered by Sealab. Germination was successful in 29 of the 30 pots planted 
with this seed, and both seeds germinated in 27 of these pots. Only one marigold and two 
Alaskan peas germinated; these died shortly after germination, reaching a height of only a few 
centimeters. When Sealab was brought to the surface, the barley, which grew to a maximum 
height of approximately 18.5 cm (7.5 in.), was cut off at the soil level, dried, and sent to Texas 
A & M for chemical analysis. A control experiment is planned by Texas A & M in which similar 
seeds will be germinated and grown under normal pressure and Sealab atmosphere, and under 
normal pressure and atmosphere. The results of these experiments, along with a complete 
report of the Sealab plant experiment will be the subject of a report by Texas A & M University. 



360 OCEANOGRAPHIC INVESTIGATIONS 



BOTTOM-ROUGHNESS POWER SPECTRUM 



The power spectrum of bottom roughness is a function needed as an environmental input 
for statistical theories of sound scattering from sea bottoms. Since no such data exist for 
real ocean bottoms at Sealab II depths, it was desirable to attempt measurement of bottom 
roughness, using a technique which has been tested at shallow depths and sandy bottoms in the 
Gulf of Mexico. This technique involves establishing a reference baseline about 3 in. above 
the bottom in the form of a tightly stretched nylon line; measurements from this baseline to 
the bottom are then made at preselected equispaced intervals, yielding a series of data points 
from which variance of the bottom topography as a function of space frequency can be calcu- 
lated. A suitable area of bottom was located near the visibility range, about 30 m (100 ft) 
upslope from Sealab II. The general appearance of the bottom revealed random irregularities 
in the form of depressions and bumps (with relief of approximately 1 to 2 in) probably caused 
by biological activity, and weak, highly irregular ripples (with relief of approximately 1/2 to 
1 in.) probably caused by waves and currents. These features appeared to be isotropic and 
homogeneous over the area considered. Unfortunately, on the first attempt to make measure- 
ments as described above, it was found that the presence of the thin layer of easily disturbed 
fine silt at the bottom was a critically limiting factor. Invariably and unavoidably, as the two 
divers adjusted themselves and moved equipment into position to get data, enough silt was 
stirred into suspension to completely occult the field of view where measurements were being 
made. For this reason, and for lack of time to adequately modify the measurement techniques, 
this experiment was not successful, and no useful data were obtained. Modified techniques to 
get around this problem are being worked on, so that in future work it will be possible to make 
measurements of bottom roughness in both sandy and silty regions. 

DIFFUSION STUDIES OF BOTTOM BOUNDARY LAYER AND NEAR-BOTTOM TURBULENCE 

It was planned to photograph dye and/or neutrally buoyant particle movement near the bot- 
tom in order to study turbulence in and above the bottom boundary layer. This work was not 
successful for a combination of reasons. 

1. Primarily, as with the bottom- roughness power- spectrum study, presence of the layer 
of fine silt which was unavoidably stirred into suspension prevented effective use of cameras 
and dye drops near the bottom. 

2. This experiment would have been much more time consuming than others in the plan, 
so that relative to the limited amount of diving time available (at suitable distances from Sea- 
lab) it was felt this study should be of relatively low priority. 

3. It proved much more difficult than anticipated to provide accurate and reliable movie 
coverage for experiments such as this; again, available diving time was a limiting factor. 

ULTRAVIOLET FLUORESCENCE STUDY 

Sealab II offered a unique opportunity to observe, both at night and in weak daylight, the 
effect of exposing marine organisms and bottom sediments to ultraviolet light. However, since 
such a study would be completely qualitative and exploratory, it was considered to be low in 
importance relative to many others planned. A speciaUy waterproofed ultraviolet light was 
constructed for use from Sealab II. As it turned out, the difficulty of getting sufficient time in 
the water to do experiments was such that this experiment, along with several others planned, 
was never attempted. The desirability of conducting this type of experiment, however, remains 
for future Sealabs for which, hopefully, there will be a larger ratio of outside-to- inside time. 

WAVE -INDUCED BOTTOM MOTION 

It was planned that motion of near-bottom particles resulting from passage of surface 
swells would be photographed in such a manner as to correlate with a simultaneous pressure 
record from the same swells, thus allowing direct measurement of pressure- velocity phase 
relationships in or above the wave- induced boundary layer. This experiment was not success- 
fully completed for the simple reason that surface waves were never of sufficient height to 



OCEANOGRAPHIC INVESTIGATIONS 361 

cause near-bottom particle movement of the amplitude needed for adequate accuracy. At the 
depth of Sealab II, wave-induced bottom motion was observed only for waves with periods longer 
than 10 sec. On the several days that wave- induced motion was observable at all at Sealab, 
measurements showed that the period was 11 to 13 sec, and horizontal amplitude of particle 
motion never exceeded 5 cm (2 in.). It is concluded that in general this type of experiment 
will be successful only in shallower water, and hence does not lend itself to future Sealab efforts. 

MEDIUM SCALE TURBULENT DIFFUSION OF BOTTOM TRAILERS 

It was planned to track quantitatively several types of bottom drifting objects undergoing 
turbulent diffusion in the range of turbulence scale sizes 1 to 100 ft. Such data from the sea 
floor are potentially useful in developing theories to understand and predict the spread of 
almost neutrally buoyant objects from marine disasters. The technique for performing this 
experiment was to have been as follows. After releasing five to ten nearly neutrally buoyant 
objects at a preselected spot, special small marker buoys would be dropped periodically near 
each one (as it disperses) to mark its position at known times. Thus, after these objects have 
dispersed approximately 100 ft from their origin, their paths have been essentially recorded on 
the bottom. Then, by use of the compass roses and surveyor's tapes (previously described in 
"Underwater Surveying and Mapping"), the location of each marker would be determined and 
a map made which is essentially a Lagrangian plot of each object's movement. These data 
may then be applied to theories of turbulent diffusion. It is obvious from the above discussion, 
that a large amount of diving time (namely, three to five hours) would be required for each 
trial of this experiment; prior to entering Sealab it was hoped that such times would be avail- 
able. As has been pointed out already, of course, such diving times were not available; hence 
this study was not successfully completed. However, this experiment was carried out in a 
qualitative manner by releasing standard plastic Woods Hole Oceanographic Institute bottom 
trailers on a daily basis and observing their general behavior pattern. These bottom trailers 
are numbered, addressed, and have a reward statement affixed so that if one is found by a 
trawler, diver, fisherman, or beach comber, its location will be forwarded to Woods Hole, 
thus providing information about bottom currents. Their design is such that a current of a 
few hundredths of a knot will move them. In all, about 200 of these bottom trailers were re- 
leased. 

Observation of these bottom trailers indicates that their diffusion rate was typically very 
slow; on several occasions those released on a previous day were observed a day later within 
10 ft of the release point. On Sept. 22 trailers were found in the release area which had been 
released 1,2, and 6 days earlier. This slow rate of diffusion was another reason that the 
quantitative aspects of this experiment were not successful. 

The main sources of movement for the bottom trailers were the quasisteady bottom cur- 
rents (associated with tides or seiches) which, although weak, were sufficient to transport 
them. Thus, if movement due to such currents is neglected, it appears that an approximate 
upper limit on the diffusion transport rate by medium- scale turbulence is of the order of a few 
tens of feet per day. It is expected that current-meter records will yield data about current 
fluctuations which can be analyzed from the point of view of the turbulent components of the 
current, and hopefully, correlated with bottom-trailer observations. 

FISH-BEHAVIOR STUDIES 

Sealab offered the opportunity of making long-term, detailed studies of the behavior, and/ 
or reactions of various marine organisms to manmade objects placed in their natural environ- 
ment. To take advantage of this opportunity, the writers had planned a number of observational 
studies. As it turned out, it was not possible to complete any of these investigations, success- 
fully, all of which had a fairly low priority in terms of the overall planned program and naval 
applications. Data provided by these studies, however, do have direct application in fisheries 
research and in the utilization of the products of the sea, and these studies should be considered 
for future Sealab efforts. The primary reason for not attempting these research tasks as 
planned was that the available bottom time was far less tha,. had been expected; other reasons 
are described below, along with a description of the proposed effort and the expected results. 



362 OCEANOGRAPHIC INVESTIGATIONS 

Attraction of Marine Animals to Objects Placed on the Sea Floor 

It is known that objects placed on the sea floor attract various forms of marine life. For 
example, the writers have observed that fish are attracted to mine cases within minutes after 
plant, and the population becomes more concentrated during the first month of exposure. It 
was planned to place several mine cases at varying distances from Sealab, inspecting these 
periodically and recording the types, number, and behavior of the various organisms attracted 
to these objects. The writers were unable to plant these objects as planned (during Team 1 
occupancy of Sealab), since the bottom had not been adequately surveyed; hence it was ques- 
tionable if the mines could be relocated for observational purposes. During Team 2's occupancy 
of Sealab, the writers surveyed the bottom and inspected several possible sites for this exper- 
iment. It was decided, however, that it would be impractical to attempt this study as planned, 
since Sealab had affected the ecology of a much greater area than had been expected. Hence 
the mine cases would have had to be placed several hundred feet away, requiring at least 30 
minutes bottom time of two divers to make these observations. 

Study of the Animal Shadow Zone in the Lee of Sealab 

It has been noted that various forms of marine life, fish in particular, are attracted to the 
upcurrent side of large objects placed on the sea floor. It was planned to study this phenomena 
during Team 2's occupancy, making population counts on both sides of Sealab, the power hive, 
PTC, and the benthic lab. The low- current regime which prevailed throughout Team 2's oc- 
cupancy made this study impractical. 

Study of the Reaction of Bottom Fish to a Low Barrier. 

It has been noted that certain bottom fish will swim around a barrier that happens to be 
in their path rather than swim over it. This appears to be true even if the barrier is only 
one to two feet high, but many feet in length. It was planned to construct a small fence outside 
Sealab and make observations of the reaction of the fish to this barrier through a porthole win- 
dow. The low light level and visibility conditions which prevailed near the bottom during Team 
2's occupancy of Sealab made this experiment impractical. 

CONCLUSIONS AND RECOMMENDATIONS 

In this section are presented those conclusions and recommendations regarding ocean- 
ographic research from Sealab- type habitats which appear valid and useful at this time. Also 
included are some discussions of subjects which, while not directly concerned with oceanogra- 
phy, definitely limit the amount and quality of work attainable; these items are discussed from 
the point of view of providing more diving time per day per oceanographer. It is felt that, as 
far as doing oceanographic research is concerned, diving time should be at least four hours 
per day. In Sealab 11 it was difficult to attain even two hours per day, and much of this time 
was devoted to logistics and housekeeping. We will not discuss in detail the most critical sin- 
gle "bottleneck" of Sealab II, the entry way and staging area; it is notoriously obvious by this 
time that these areas need to be several times as large as in Sealab II, that divers need to be 
able to work all around the entry well, and that the entry ladder needs to be of a type suitable 
for divers to climb. Several recommendations concerning philosophy and design of Sealab will 
now be discussed. 

The established and recognized policy of Sealab II was that team members be primarily 
divers; assignments associated with specialization and/or skills were of secondary importance 
relative to being a diver. ='= Now that this approach has been tried, it is recommended that the 
established crew operating policy of the rest of the Navy be utilized in the future, namely, that 



*Project Manager's Note: A number of recommendations on team make-up and Sea Habitat or- 
ganization have been made by the various aquanauts , this being one rationale. Sealab II was 
conducted as the first multidiscipline saturated diving experiment, and there were even great 
differences of opinion between divers concerned with the same ocean-floor problem, i.e., sal- 
vage divers, as well as differences between Teams 1, 2, and 3. 



OCEANOGRAPHIC INVESTIGATIONS 363 

crew members be assigned primary tasks associated with particular skills and that responsi- 
bility for these tasks be at least as important as for diving tasks. It is believed that more ef- 
ficient accomplishment of work both outside and inside Sealab will result from this approach. 
Note that this recommendation does not imply discarding the important concept that all crew 
members be fully trained and responsible for operation and use of all diving gear and all sys- 
tems which are part of the Sealab. 

It is recommended that effort be devoted toward reducing the acoustic noise level both in- 
side and outside Sealab. For future work at great depths it would be highly desirable to have 
Sealab noise levels sufficiently low that ambient noise of biological origin can be measured 
without undue masking by background noise. 

One or more special-purpose portholes should be provided. One such porthole should be 
mounted to provide a view of the outside region through which divers enter and leave Sealab, 
its purpose being to allow determination of whether or not a diver is in trouble. In both Sealab 
I and II most of the situations in which divers were in real trouble and had critically short time 
available occurred at or just outside the shark cage. Also, it is nearly unavoidable that divers 
be occasionally alone in this area for short times. The ability to see such divers from the in- 
side would be a valuable safety feature. 

Another type of special- purpose porthole is suggested by the fact that the field of view 
from any porthole in Sealab II was very narrow. To observe adequately the behavior of active 
animals such as sea lions was not possible because of the narrow, nonoverlapping fields of view 
from Sealab II. One way to obviate this problem would be to provide a cylindrical glass port 
of the pillbox type at the top and/or on each side of future Sealabs. Such viewing ports are 
mechanically simple and rugged, yet provide much larger fields of view. 

It should be noted that the potential of porthole observations for acquisition of scientific 
data (particularly in biological studies) has not been nearly fully exploited; plans should be 
made to do so in future Sealabs. It should also be realized, however, that erroneous impres- 
sions can be gained from porthole observations, particularly as regards water current and 
motion. For example, in Sealab II it was noted on occasion that water was going down by one 
port hole and, at the same time, going up by an opposite port hole. This type of flow, typical 
of that around a cylinder at high Reynolds number, consists of eddy shedding and unsteady 
movement of the stagnation point around the periphery of the cylinder. By viewing such flow 
from inside the cylinder it is very difficult to infer accurately details of the outside flow away 
from the cylinder. It should be possible, however, to place a set of flow and/or pressure sen- 
sors on a cylinder such as Sealab so that (with appropriate averaging techniques) current speed 
and direction can be accurately recorded. Consideration should be given to the idea of provid- 
ing such special oceanographic instrumentation for future Sealabs; this concept is discussed 
more fully below. 

Turning from Sealab design features, we now discuss results of evaluating Sealab II as an 
oceanographic platform and make recommendations for future Sealab oceanographic programs. 

In the preliminary proposal for MDL participation in the Sealab II program, it was pointed 
out that Sealab might well be the long- sought- after stable platform from which to measure 
waves, currents, and tides and from which to obtain badly needed information on near-bottom 
features of such scale that the trained and interpreting human eye is needed for decisions about 
deployment of instruments and correlation of observations. Experience gained through partici- 
pation in Sealab II yields the conclusion that Sealab platforms do indeed provide the capability 
to attack effectively these and many other significant oceanographic problems, the solution of 
which would lead to a better understanding of the marine environment and how to e.xploit it. 
Sealab II, however, was not specifically designed as an oceanographic platform, and it is obvi- 
ous that certain modifications, and/or additions (some of which have been discussed in preced- 
ing sections) would greatly enhance its oceanographic capabilities. A particularly valuable 
specific addition for future Sealabs would be the inclusion, as an integral part of the design 
concept, of special oceanographic instrumentation. This instrumentation, although initially 
expensive, can be designed for adaptation to all future Sealab habitats. Included in this instru- 
ment array should be sensors for measuring temperature, currents, light level, salinity, sound 
velocity, ambient noise, pressure fluctuations, tides, bioluminescence, water clarity, and others, 



364 OCEANOGRAPHIC INVESTIGATIONS 

as necessary. Many of these sensors should have the capability of making measurements from 
the bottom to the surface. There are presently available from commercial sources instrument 
packages which provide many of the features required; also, the Naval Oceanographic Office 
has similar instrumentation packages which have been successfully used aboard submarines. 

Future Sealabs appear to be particularly attractive as platforms from which to make stud- 
ies of several difficult and important oceanographic problems which are presently receiving 
considerable attention and yet are in a poor state of solution, mainly due to lack of suitable 
platforms from which to collect data. These are: (a) the air-sea interaction problem, (b) the 
bottom- sea interaction problem, and (c) the open- sea tide problem. 

Solution of the air- sea interaction problem critically depends not only on the ability to 
place sensors precisely just above and beneath the sea surface, but also to do this without 
having the wind and water flow fields disturbed by either sensor- support devices or by surface 
platforms. Also, certain chemical and boundary- condition aspects of the air-sea interaction 
problem depend critically on not having the surface contaminated in the manner which unavoid- 
ably occurs near ships or offshore towers. A unique method of solving these sensor- support 
and sampling problems will be offered by the first Sealab operation which does not have a stag- 
ing vessel moored above it. In such a situation, the open ocean surface is far enough away that 
Sealab offers no source of contamination; yet by means of subsurface floats (let up from the 
bottom), sensors and/or samplers can be placed at the sea surface with accuracy, with mini- 
mum disturbance, at sea states for which data would be unobtainable otherwise. 

The bottom- sea interaction problem is another boundary problem which requires judicious 
and accurate placing of sensors and samplers. At the present level of understanding, this prob- 
lem is best attacked by having the trained scientist make direct observations at the sea floor. 
Future Sealabs are obviously the best platforms from which to do this, especially for depths 
greater than 200 ft and for extended times. 

The open- sea tides are in an imperfect state of understanding simple because of lack of 
accurate tidal data from offshore regions. As Sealabs extend to deeper depths and larger dis- 
tances from shore, there are no r>3asons why they should not assume major importance as a 
source of open- sea tide data. 

Finally, it should be emphasized that the consideration which gave rise to formulation and 
inclusion of an oceanographic research program for Sealab II are equally valid and significant 
for Sealab in. This is especially so when one realizes that the sea floor at Sealab m will be 
at depths which no scuba- equipped scientific diver has ever explored. Several tasks underta- 
ken from Sealab II, of significance to both the Navy and the oceanographic community, should 
be investigated further from Sealab III. In short, it is strongly recommended that an ocean- 
ographic program be included in Sealab III which takes advantage of experience gained in Sealab 
11, utilizes as fully as possible the combination of recording instruments and the in situ trained 
eye, and provides for acquisition of new data from previously unexplored depths. 

REFERENCES 

1. Dowling, G. B., "Divers' Instiumented Observation Board," U.S. Navy Mine Defense Lab- 
oratory Report No. 210 (Unclassified), July 1963. 

2. Tolbert, W. H., Payne, R. H. and Salsman, G. G., "An Underwater Crane," Limnology and 

Oceanography 9(1): 150-151 Man. 1964) 

3. Salsman, G. G. and Tolbert, W. H., "Observations on the Sand Dollar, Mellita Quinquies - 
perforata," Limnology and Organography 9(1): 152-155 (Jan. 1965) 

4. Austin, Roswell W., "Water Clarity Meter Operating and Maintenance Instructions," Visi- 
bility Laboratory, University of California, Scripps Institute of Oceanography Reference 
59-9 (Feb. 1959) 

5. Harvey, Edmund U., "Bioluminescence," New York: Academic Press, 649 pp., 1952 



OCEANOGRAPHIC I^WESTIGATIONS 365 

6. Nicol, J. A. C, "Luminescence in Marine Organisms," Smithsonian Report, pp. 447-456 
(1961) 

7. Seliger, H. H., Fastie, W. G., Taylor, W. R. and McElroy, W. H., "Bioluminescence of 
Marine Dinoflagellates," The Journal of General Physiology, Vol. 45, No. 5 (May 1962) 



chapter 40 
THE SEALAB II BIOLOGICAL PROGRAM 

A. O. Flechsig 

Scripps Institution of Oceanography 

University of California 

La Jolla, California 

The aim of the Scripps Institution of Oceanography biological program in Sealab II was to 
describe the biological activity in, on, and just above the sea floor in the vicinity of the habitat 
and as far away as the divers could operate with safety. The program was designed to de- 
scribe the normal bottom fauna and to document any qualitative or quantitative changes that 
took place after Sealab was placed on the bottom. To do this we needed: 

1. To determine the identities, abundances, and spatial distributions of the organisms at- 
tracted to the Sealab site throughout the operation and to compare and contrast these with the 
normal sandy-bottom and canyon faunas. 

2. To record the activities of organisms and their relationships with each other and with 
the physical environment. This included studies of schooling, predator- prey relations, the 
effects of light, etc. 

Our program required: 

1. That organisms be collected for identification and stomach analysis. 

2. That organisms be counted at diverse places and times to determine their abundances 
and spatial and temporal distributions. 

3. That photographic observations be taken of the activities of organisms to study their 
behavior and their relationships with the environment. 

To meet these requirements, the program was planned to use techniques and instruments 
proven successful in shallow-water diving. In some cases there was anticipation of the need 
for modification of these for the particular circumstances of the operation. There were also 
several planned experiments. These included modification of the environment by construction 
of block pyramids and behavioral studies in large wire- mesh holding cages. 

It was possible to carry out an extensive survey of the organisms present around Sealab, 
although investigators were hampered by insufficient diving time. Available data indicate that 
an object the size of Sealab provided with lights is a very effective fish attractant. By the end 
of 44 days some 6,500 fish, representing 15 common species, were present. Over the entire 
period a total of 47 species were observed. This is a much more rapid buildup of fish popula- 
tions than has been observed at larger, shallower artificial reefs along the California coast, 
presumably as a result of the presence of lights. Observations of predatory and other behav- 
ioral interactions, and of patterns of distribution, coupled with studies of collected specimens, 
have given a preliminary idea of the structure and dynamics of the community of animals, par- 
ticularly fish, attracted to such artificial substrates. 

Following is a list of equipment and procedures intended for use during the Sealab II proj- 
ect. Appended to each item is an estimate of its effectiveness and probable causes for inade- 
quate performance. 



366 



BIOLOGICAL PROGRAM 367 

1. Collection of specimens by spear, net, etc.— performance: good: coverage: adequate 
for identification purposes. More systematic collections for stomach analysis would have been 
valuable, but were not taken owing to insufficient diving time and scheduling difficulties. 

2. Corer for collecting substrate samples to determine identity, abundance, and distribu- 
tion of small subsurface dwelling organisms— coverage: good: performance: adequate, but a 
faster method designed specifically for handling the fine sediment would have saved much div- 
ing time. 

3. Fish rake for censusing larger animals on the bottom— coverage: barely adequate ow- 
ing to insufficient diving time: performance: fair, owing to insufficient lead time to test the 
apparatus and modify the techniques of use for Sealab conditions. 

4. Multiple- level plankton net sled for censusing near-bottom plankton— not used because 
of hazards from scorpion fish on the bottom near Sealab and insufficient diving time to go fur- 
ther away. 

5. Permanent station template for independent estimates of abundance and determining 
movements of small organisms— not used; conditions near Sealab and insufficient diving time 
did not warrant setting up the stations. 

6. Concrete block pyramids for comparison with Sealab as environmental modifications- 
performance: fair, placed on the bottom much later than desirable owing to insufficient diving 
time and logistic difficulties. 

7. Wire- mesh cages for holding experimental animals— not used because of insufficient 
diving time. 

8. Tagging larger organisms— performance adequate: coverage: poor as a result of in- 
sufficient diving time. 

9. Chemical attraction of organisms— not used owing to insufficient diving time. 

10. General observations, outside— performance: fair, hampered by poor illumination, in- 
sufficient lead time to develop tape-recording capability, preoccupation with other tasks while 
diving, and lack of opportunity to dive at times selected for their relevance to scientific objec- 
tives. 

11. General observations, inside— performance: good, but hampered by conflict of other 
duties with maintenance of regular scientific watches. 

12. Photography of organisms— performance: only fair owing both to insvifficient lead time 
to modify and test new equipment and to insufficient diving time. 

The inadequacies in performance and coverage were primarily due to three reasons: far 
less time was spent in the water than was anticipated, dives could not always be scheduled at 
times that would be best for our program, and we had very little opportunity to design, modify, 
or test equipment or procedures under conditions similar to those around Sealab prior to oc- 
cupation of the habitat. As a result, some projects took so much more time than expected that 
coverage was limited and other projects had to be eliminated. Our recommendations, which 
follow, stress these points. 

1. A greater amount of lead time should be allowed in order to develop and test equip- 
ment. Funds for acquiring and developing equipment should be available very early in the 
project. 

2. Diver training should put more stress on navigational problems and homing procedures. 

3. Diver-to-diver and diver-to-tape-recorder communication should be developed. 



368 BIOLOGICAL PROGRAM 

4. There should be provision in the training schedule for practicing the scientific tech- 
niques insofar as these are modified from standard operations or are unfamiliar to some of 
the scientist- divers. The practice should be carried out at depths and under conditions that 
will have some similarity to what will be encountered around the habitat. 

*5. Both members of a buddy pair should be scientists. If this is impossible, the scientist 
should have the opportunity to familiarize one diver with his aims and procedures. Buddy ro- 
tation is inefficient. 

6. The amount of scientific research that could be accomplished would be markedly in- 
creased if there were a crew— as there is on surface oceanographic vessels— to carry out many 
of the housekeeping tasks and if fewer conflicting projects were planned. 

7. Some means should be found to free the scientist from long periods of enforced inactiv- 
ity and unproductive watch standing during all phases of the operation. Further, assuming that 
the serious physical shortcomings of the Sealab II operation, such as limited diving facilities, 
small entryway, excessive surface traffic, etc., are corrected, the scientist should be allowed 
to schedule and execute his activities to meet the needs of his program. 

8. A project in which the scientific results are a primary end should be continued long 
enough for feedback from the early results to affect the later part of the program. Another 
approach would be to repeat the operation at intervals of moderate duration. 



^Project Manager's Note: Some Scientists felt it preferable to use a Navy diver as a trained 
observer. 



Chapter 41 
SEALAB II UNDERWATER WEATHER STATION 

E. A. Murray, D. L. Inman, and W. A. Koontz 
Scripps Institution of Oceanography 
University of California 
La Jolla, California 

INTRODUCTION 

An underwater weather station was installed near Sealab II and maintained by the aquanauts. 
The weather station measured water current, direction, pressure, temperature, and ambient 
light. It was intended that these measurements provide the divers with the most essential pa- 
rameters of underwater weather, as well as necessary background information for other sci- 
entific programs undertaken during the operation. Li addition, it was hoped that the under- 
water weather station measurements, when compared with similar measurements obtained 
synoptically elsewhere on the shelf, would provide insight into the complex phenomena that 
constitute underwater weather. 

There are almost no continuous observations of the underwater environment that are of 
sufficient scope to be considered as underwater weather. Yet, underwater weather is as im- 
portant to man in the sea as to man in the atmosphere. The kinds of parameters to be sensed 
are similar to those in the atmosphere: current speed and direction, pressure, temperature, 
and light. Their measurement underwater is somewhat more complicated, principally because 
water is wet. In addition, the underwater environment has greater pressure, viscosity, specific 
heat, and biological activity of all kinds. The importance of biological activity is frequently 
overlooked in underwater instrumentation. Every few days, it was necessary to clean organic 
growth and fouling from the current meters. The current measured underwater appears de- 
ceptively weak in terms of air currents. However, "gusts" up to nearly two knots were mea- 
sured near Sealab and these, because of the increased density and viscosity of water, would 
have exerted a drag on the diver equivalent to that of a 50 to 100 knot wind in the atmosphere. 

Sealab II, with three teams of divers and a total underwater occupancy of 45 days, pre- 
sented an excellent opportunity to obtain long-period continuous measurements of the under- 
water environment. 

DESCRIPTION OF THE AREA 

The site of Sealab II was the continental shelf just north of La Jolla, California, where 
Point La Jolla forms a small hooked bay which opens to the northwest. The shelf area within 
the embayment is cut by two main branches of La Jolla Submarine Canyon (Fig. 136). Sealab II 
was placed on the rim of the northern branch, Scripps Submarine Canyon, where the rim has a 
depth of about 210 ft; the floor of the adjacent canyon has a depth of 650 ft. Both La Jolla and 
Scripps Canyons extend across the continental shelf and terminate within a few hundred feet of 
the beach. The shelf between the two canyons is covered with fine sand in shallow water and 
with fine sand and coarse silt at the Sealab II site (1). Scripps Canyon is narrow and precipi- 
tous, and in many places the walls are vertical as indicated by observations from the diving 
saucer (2). 

For many years it has been known that the heads of Scripps Canyon trapped sand from the 
adjacent beaches. This beach sand is eventually deposited in the deep water of San Diego 
Trough, some 16 to 20 miles seaward. The mechanism by which the sand is transported through 

369 



370 



UNDERWATER WEATHER STATION 



117* 17 



32* 52' 




32*5I" 



Fig. 136. Index chart showing bathymetry of the Continental Shelf off La JoUa, California. 
The Sealab II site is indicated by the dashed area, and its position and detailed bathymetry 
are shown in Fig. 138 



UNDERWATER WEATHER STATION 371 

the canyon is not understood, although the volume of material transported has been measured. 
Extensive surveys of the canyon head (3) indicate that about 200,000 cubic yards of sand is lost 
into the canyon each year. A series of current measurements have been made over periods of 
days and weeks at several stations within the canyon. One of these stations is within scuba div- 
ing depth at 150 ft at the head of the canyon (Fig. 136). Currents have also been measured on 
the canyon floor just below the Sealab site at a depth of 650 ft. These measurements were ob- 
tained by sending a self-contained instrument package down a taut -wire mooring to the canyon 
floor (Fig. 137). After a predetermined length of time weights are released, and the instrument 
package returns to the surface, where it is retrieved by scuba divers. The 650-ft station was 
not occupied during the Sealab measurements because of fouling by the mooring lines from the 
surface support vessel, Berkone. However, a taut-wire mooring at a depth of 215 ft just north- 
west of the Sealab II site was instrumented during the Sealab operation (Fig. 138). There data 
were compared with data from the underwater weather station which was at a similar depth on 
the rim northeast Sealab II. 

INSTRUMENTATION 

Data from all sensors except the two current meters at the bottom of the canyon were 
transmitted to a control center (called 'TDenthic control") at the shoreward end of the pier, 
where it was recorded in both digital and analog form. Pier-end data were transmitted by di- 
rect cable, but data from the weather station were transmitted through a telemetry system 
which had its seaward terminal in an underwater benthic chamber. Six 2-conductor cables and 
three 4-conductor cables connected the instrument array on the weather station platform to an 
equipment rack inside Sealab. The equipment rack furnished power for the sensors and con- 
ditioned the signals from the sensors for transmission via the telemetry system. It was es- 
sential that the variable -resistance sensors receive a constant excitation current. It would 
have been impractical to furnish an individually regulated constant-current supply for each 
sensor, so a single 300-volt constant- voltage supply was installed. Individual 300,000-ohm re- 
sisters connected to the 300-volt supply furnished an excitation current of one millampere for 
each sensor. Since the resistors were mounted in Sealab, the amperage available in the water 
was very low. A 12-volt power supply, also mounted in the equipment rack, furnished regulated, 
constant -voltage power at about 3/4 ampere for electronics packages incorporated in the cur- 
rent members and the Vibrotron pressure sensor and for signal power amplifiers in the equip- 
ment rack. 

An analog-to-digital converter inside Sealab changed the signals from variable-resistance 
sensors to digital form to be transmitted via the telemetry system. Signals from the current 
meters and the Vibrotron needed no transformation. All sensors except the Vibrotron could be 
monitored inside Sealab with Rustrak chart recorders. Digital channels of 12 bits each were 
sampled every 6 or 12 seconds by the analog -to -digital converter. Some of the more important 
data channels, including the current and pressure sensors, were connected directly to the telem- 
etry system and could be sampled as often as desired (within limits imposed by the nature of the 
signals). However, analog signals from the variable-resistance sensors could be telemetered 
with any great accuracy due to drift in the telemetry channels. 

All signals were connected from Sealab to the underwater benthic telemetry chamber via a 
multiconductor cable. From here they were transmitted to the shore station via an amplitude- 
modulated, multichannel carrier telemetry system on a single coaxial cable. 

Savonius Current Meter 

Accurate measurement and recording of low-period, low-velocity undersea currents 
prompted a modification of the reliable and time-tested Savonius rotor (Fig. 139). A miniature 
model, designed by Mr. J. M. Snodgrass of the Scripps Institution of Oceanography, was con- 
structed of "Cycolac" plastic sheet and balanced to be neutrally buoyant in sea water. The 
rotor was mounted on bearings of sapphire and tungsten carbide. Sixty equally spaced holes 
near the periphery of one rotor end plate interrupted a light beam as the rotor turned, produc- 
ing 120 electrical pulses for each revolution. One pulse was generated as the beam passed 
through each hole, and another pulse was generated as the beam was interrupted. This pulsing 
output signal has proven to be most reliable in transmitting data over long telemetry channels 
because its information is relatively immune to amplitude modulation caused by normal noise 
pickup during transmission. 



372 



UNDERWATER WEATHER STATION 







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Fig. 138. Detailed Bathymetry in the Vicinity of Sealab II. Numbers 
show the locations of: (1) Benthic lab, (2) power beehive, (3) under- 
water weather station, (4) taut-wire mooring on canyon rim, and (5) 
taut-wire mooring on canyon floor. 



374 



UNDERWATER WEATHER STATION 




Fig. 139- Aquanaut Murray holds the upper 
(right) and lower (left) current meter pack- 
ages prior to installation 



Several light sources for the current meter were tested during its development. The final 
design incorporated a CM-8 series bulb manufactured by the Chicago Miniature Lamp Works. 
The bulb, because of its small size, was capable of withstanding the high pressure of the en- 
vironment and proved to be less susceptible to marine growth than larger lamps which were 
tested. 

Direction of current flow was indicated by a Cycolac vane mounted on sapphire pivots and 
housed axially with the Savonius rotor. Vane position was sensed electrically by a potentiom- 
eter, and its analog readout appeared inside Sealab. A magnet was attached to the potentiom- 
eter shaft and the unit sealed in an oil-filled canister. A second magnet fastened to the edge 
of the vane provided magnetic coupling of vane rotation with potentiometer rotation. The oil 
damping reduced overswing of the potentiometer during fast transitions. 



Vibrotron Pressure Sensor 

The Vibrotron is a vibrating-wire transducer which converts absolute pressure input to 
an output signal with a frequency inversely proportional to the applied pressure. It was chosen 
for use at the sea-floor weather station because of its ability to resolve small changes in ab- 
solute pressure while in a very-high-pressure environment. Excitation and signal amplification 
electronic circuitry was modularized and housed with the transducer in an oil-filled canister. 
The audio output signal was telemetered directly to the data acquisition system on shore where 
the frequency variations were digitized and recorded on magnetic tape along with the other 
measured parameters. 



UNDERWATER WEATHER STATION 375 

Data Acquisition System 

A system of analog and digital recorders, along with necessary amplifiers, digitizers, and 
logic control units, was located in the benthic control center near the telemetry receiving ter- 
minal equipment. A 12-channel chart recorder monitored analog readouts from the underwater 
weather station and from the pier end anemometer. A separate chart recorder monitored an 
analog conversion of the output of the pier end digital wave staff. The chart speed of the latter 
recorder could be changed as desired to obtain short records of wave profile (Fig. 140), as 
well as long-term records of lower frequency phenomena such as tides and shelf seiche. 



290 
200 




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150 
TIME IN SEC 



Fig. 140. Wave record from the digital wave staff mounted on the end of the Scripps In- 
stitution of Oceanography Pier. Record begins at 1200 PST, Oct. 6, 1965, and is repre- 
sentative of waves contributing to the spectrum in Fig. 144. 



The telemetry receiving equipment monitored the output of the analog-to-digital converter 
in Sealab and recorded the information incrementally on magnetic tape. Data which were telem- 
etered direct (without conversion) were channeled into a data-acquisition system (DAS) for 
sampling at shorter time intervals. Plug-in, printed-circuit logic boards were used in the ac- 
quisition system to digitize the sampled data, to store in memory banks in binary form infor- 
mation from all input channels, and to present the information in increments to a high-speed 
magnetic tape recorder for permanent storage. The tape record was in standard IBM format 
and could be programmed directly into a computer for analysis. 

INSTALLATION OF UNDERWATER WEATHER STATION 

The underwater station platform was lowered to the sea floor from the staging vessel 
Berkone on the evening of Sept. 4, 1965. The platform in its lowering position (Fig. 141) con- 
sisted of a central 1/2-in. -thick steel plate, 32 x 32 in. on a side, to which were welded four 
leg guides and two instrument mounting brackets. Other components, including the taut wire 
and its float and the flotation equipment, were lashed to the platform between the four anchor 
legs, which in their lowering position form a "teepee" structure. Once on the bottom, the plat- 
form was located in the turbid water by two divers using a 25-40 kc hand-held sonar. A 37-kc 
"pinger" attached to the platform provided a target for the sonar. 

The underwater weather station was diver-oriented in its design. It was intended that it be 
easily moved by two divers after inflating four rubber tubes to give it neutral buoyancy. The 
tubes were inflated by bleeding air from a scuba bottle into holes cut in the tubes near their 
point of attachment. This arrangement provided the necessary safety control to prevent over- 
inflation and excess positive buoyancy. The air in the tubes could be spilled instantly by squeez- 
ing the tube. After inflating the tubes, the platform was transported 165 ft to the installation 
site by two divers. The site (Fig. 138, position 3), which had been determined previously dur- 
ing reconnaissance dives, was on a slight rise where currents would be more typical of the 
area than in the valley at the Sealab site. The platform was firmly anchored in place by four 
anchor pounded legs into the bottom. The taut-wire mooring was then released from the plat- 
form and assumed its vertical position, maintained in a taut position by the 75-pound positive 
buoyancy of the float. At the end of the 45-day Sealab project, all of the underwater weather 
station sensors were attached to the taut-wire mooring, which was then released from the 
platform and retrieved on the surface. 



376 



UNDERWATER WEATHER STATION 



LOWERING POSITION 



DIVER TOWING POSITION 



INSTALLED 





TUBES 
INFLATED 




Fig. 141. Schematic diagram of the Sealabll Underwater Weather Station in lowering posi- 
tion, diver-towing position, and installed position. Numbers indicate sensors: (1) upper 
current speed, Savonius rotor, (3) compass, (4) upper thermistor, (5) lower current speed, 
Savonius rotor, (6) lower current direction vane, (7) pressure sensor, Vibrotron, (8) lower 
thermistor, (9) ambient light 



Two days were required to install sensors on both the upper and lower weather station. 
Conductors were run to the station, and underwater weather was recorded in the habitat. Two 
trips were made daily to service instruments and check sensors. Recorders inside the habitat 
were checked, and comparisons with observed weather conditions from the 24-inch ports were 
made. 



RESULTS 

Data were recorded in analog form in Sealab 11 and in benthic control center. Also, all 
data transmitted over the benthic lab cables were routinely sampled, digitized, and then stored 
on the telemetry system's magnetic tape recorder. Unfortunately, an erratic fluctuation of the 
time -identification channel made much of this magnetic tape data unintelligible. 

The routine analog recording through the long lines of benthic lab had high levels of back- 
ground noise, as well as long-period, quasi- systematic fluctuations that partially obscured the 
data signals. Therefore, it was not practical to make a systematic reduction of all of the ana- 
log data. Rather, the approach was to (a) analyze those records that presented synoptic infor- 
mation from a number of stations, such as the underwater weather station, the 150-ft station, 
and the pier end (Figs. 142 and 143) and (b) make detailed analysis during times of unusual 
phenomena, such as high waves (Figs. 140 and 144). Detailed analysis was facilitated by the 
use of a high-speed data acquisition system, DAS, which stored data of finite length for future 
spectral and cross-spectral analysis. 



Presentation of Data 



Seven days of synoptic measurements of currents at the Sealab II underwater weather sta- 
tion and at the 150 ft deep station in the head of Scripps Submarine Canyon were made (Sept. 
22-26 and Sept. 29-Oct. 1, 1965). Comparison of currents from both localities during two days 
when the currents were most active are shown in Figs. 142 and 144, together with measure- 
ments of tide and wind from the Scripps Pier. 



UNDERWATER WEATHER STATION 



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Currents at both stations showed a marked tendency for flow directions to parallel the 
axis of Scripps Submarine Canyon rather than to cross the axis. This permitted the currents 
to be plotted as two-dimensional currents using the notations "onshore" and "offshore," where 
these notations indicate flows in the directions of 060° True and 240° True respectively. On 
Sept. 25, 1965 (Fig. 142), maximum currents in excess of one-half knot were measured at the 
underwater weather station, while those in the canyon head were in excess of one knot. Cur- 
rents at both stations were irregular in speed and showed frequent reversals in direction. The 
fluctuations at both stations had periods ranging from about five minutes to over one hour. It 
is impossible to determine from these analog records whether there is coherence in the fluc- 
tuations between two stations. It does appear that the fluctuation frequencies are similar at 
the two stations, and it is obvious in this case that the stronger currents occur at the canyon 
head. There is some indication, especially at the Sealab station, that the net current is off- 
shore ebb tide and onshore during flood tide. 

Similar comparisons between the Sealab site and the 150-ft station are shown for Sept. 22 
(Fig. 143). These differ from those in Fig. 142 in that the currents were stronger at the Sealab 
site than at the canyon head. They are similar in that both records show fluctuations of cur- 
rent with periods of a few minutes to over an hour and in that the reversals in current were 
somewhat more frequent at the canyon head. This data differs from Fig. 142 in that the net 
current appears to be onshore during most of the day. 

High waves were observed on Oct. 6 (Figs. 140 and 144). Inspection of the analog record 
from the wave staff on Scripps Pier, where the water is 20 ft deep, showed that the waves were 
as high as 6 ft (200 cm) and had periods ranging from less than 8 sec to over 16 sec. The wa- 
ter was too rough for scuba divers to place the current meter in the head of Scripps Canyon. 
However, a two-hour record of wave height from the end of Scripps Pier and current and pres- 
sure records from Sealab II were made on the high-speed data-acquisition system. During this 
run, each sensor was sampled every two seconds, and the data was processed through the CDC- 
3600 computer to obtain the spectra and cross-spectral analysis for all channels. These data 
are shown in Fig. 144, together with the phase and coherence between the Sealab pressure sen- 
sor (7) and the current (5). The spectrum from the wave staff (sensor 13) shows the surface 
wave energy to be concentrated over a broad band of waves varying in period from about 8 to 
16 sec. It also shows a pronounced long-period spectral peak with a period of about 105 sec 
which appears to represent the "surf beat" associated with these waves. Both the Sealab cur- 
rent and pressure also show broad spectral peaks with periods in the range of 10 to 16 sec, 
which are undoubtedly associated with the surface waves. The pressure record shows a series 
of spectral peaks, some (periods of 50 and 25 sec) having frequencies that are multiples of the 
surf beat frequency. Others, with periods of about 7 and 8 sec, are likely artifacts due to para- 
sitic disturbances in the data sensing and/or transmission facilities. 

The energy density for the signal variations from the wave staff and the Sealab pressure 
sensor is expressed in units of cm^ per unit of band width, Af. The corresponding spectral 
estimate for the current is in units of velocity^ per Af. The proper scale in cm- /sec per Af 
for the current spectra is obtained by multiplying the printed scale by a factor of 0.41. The 
product of the spectral estimate (energy density) and the band width gives the mean square ve- 
locity associated with any particular frequency band. It will be observed that the root-mean- 
square velocity under the broad spectral peak of the current is approximately 5 cm per second. 

The orbital velocity associated with the passage of a simple wave of frequency f in still 
water would show a maximum onshore velocity under the wave crest and a maximum offshore 
velocity under the wave trough. The spectrum for this orbital velocity would show a single 
spectral peak having a frequency twice that of the wave, because the square of the onshore 
(positive) and the offshore (negative) orbital velocities has the same sign in the analysis proce- 
dure. However, the spectrum for the current meter shows good agreement in frequency with 
that of the surface waves (center of diagram) and shows little energy at twice this frequency 
(right of diagram). This can only be interpreted as an orbital velocity superimposed upon a net 
current of nearly the same speed or greater. Inspection of the analog record of current during 
this period shows that the current had a speed varying between zero and one-quarter knot, and 
the direction of flow was southwesterly or offshore. 



UNDERWATER WEATHER STATION .381 

Diver Observations 

Observations by divers were made in the vicinity of Sealab and from within Sealab through 
three of the 24-in. portholes. The first two days' observations were made outside the habitat 
because the porthole protective covers were in place; but once removed, the forward port, the 
laboratory space port, and the starboard portholes were chosen for routine observations. The 
underwater weather station was not set up, and operational until the seventh day of occupation. 

On the first two days of occupation a swimmer survey of the lab site was made with Mk-VI 
mixed-gas equipment. The two relatively higher ridges of sand that extended from the port 
quarter and starboard bow were explored. Divers carried a safety line attached to Sealab and 
used underwater sonar that was tuned to a "pinger" frequency previously placed on the Sealab 
conning tower. 

An area on the port quarter 165 ft from Sealab was selected for the underwater weather 
station, and current observations were made here during each inspection. The weather station 
platform and its equipment were placed on a sand slope near the rim of the submarine canyon. 
Anchor and nylon safety line were mainted between the Sealab shark cage and the underwater 
weather station at all times. Sediment stirred up by the divers during inspection dives was a 
problem both for the instruments as well as for safety and visibility. The distance between 
Sealab and the underwater weather station (165 ft) and the capacity of the MK-VI mixed-gas 
diving apparatus limited the time outside to 70 minutes, or about two round trips to the weather 
station. A very large part of installation time was spent placing the cables that led from Sea- 
lab to the weather station. Once sensors and cables were in place, daily routine cleaning and 
inspection trips were initiated. 

During the first four days it was possible to "hear" or feel pressure changes caused by 
the passage of surface waves. Simultaneous observations on the surface and in the habitat 
showed that occupants were able to sense on the surface and in the habitat showed that occu- 
pants were able to sense crests and troughs of waves passing on the surface. 

Observation of fish that set up permanent occupancy near Sealab portholes showed they 
definitely oriented with the current. Migratory fish appeared independent of the direction of 
current and surge. Usually the orbital motion of surface waves is not apparent from the tra- 
jectory of small particles at this depth. 

During the first three to five days of occupancy, surface waves were low, and tides were 
near their spring range (about 5 ft). Bottom currents, as indicated by particle trajectories, 
did not show good agreement with tidal fluctuations. Erratic fluctuations from onshore to off- 
shore currents were commonly observed. On the sixth day of occupancy, the height of the sur- 
face waves increased to about 60 to 8 ft, and the waves continued to be high through the tenth 
day. The high waves were followed on the eleventh day by a strong, steady offshore current. 
This current was also measured by the sensors on the underwater weather station, which 
showed maximum velocities of 1 knot and 2 knots on the lower and upper sensors respectively. 
During the first teams occupancy, each period of high surface waves was followed by: (a) an 
increased tendency for offshore current, (b) increase in water temperature, (c) increase in 
numbers of plankton, and (d) appearance of large, migratory fish. Observations over longer 
periods are necessary to determine if this is a common trend. 

REFERENCES 

1. Inman, D. L., "Areal and Seasonal Variations in Beach and Near-shore Sediments at La 
Jolla, California", Corps of Engrs., Beach Erosion Board Tech. Memo. No. 39, 1953 

2. Shepard, F. P., Curray, JrR., Inman, D. L., Murray, E. A., Winterer, E. L., and Dill, R. F., 
"Submarine Geology by Diving Saucer," Science, 145:3636:1042-1046 1964 

3. Chamberlain, T. K., "Mechanics of Mass Sediment Transport in Scripps Submarine Canyon, 
California," dissertation for Ph.D. degree. University of California, Los Angeles, 1960 



382 UNDERWATER WEATHER STATION 

DIVER LOG, AUG. 28, 1965 TO SEPT. 11, 1965 

1st Day 

No current observed on the bottom. Visibility 30 ft (porthole covers still on; all observa- 
tions today by divers). Two-in. nylon mooring lines sway slightly with the surge, estimate 1-ft 
swing. No ripple marks in the silt and sand bottom sediments. Temperature outside about 

46°F. 

2nd Day 

Removed four starboard porthole covers. Visibility 30 ft. Current observations by diver- 
onshore very slight. Observations through Sealab porthole— trajectory of plankton past glass 
port is onshore and up. Trajectory interrupted by a pause about every 6 sec, during which 
plankton "sinks" down, followed by a repetition of the onshore and up motion. Net drift onshore 
and up at the rate of 1 ft per 15 sec. This condition prevailed all day. However, sometimes 
in the late p.m., the direction reversed and plankton moved offshore and down. 

3rd Day 

No observations this date from inside Sealab. Observations outside show very slight drift 
of plankton in a downslope and southwest direction most of the day, stronger by dark. 

4th Day 

Net drift of current onshore and up. Plankton moves 24 in. in 15-1/2 sec in the a.m. Cur- 
rent decreased in velocity by noon, increased steadily in p.m. to offshore, 24 in. in 10 sec by 
dark. Current increased near sunset and was strongest at 1800. Current velocity changed 
very quickly after dark to a very slight offshore and down movement. There is still no distinct 
off and onshore surge as is commonly associated with the passage of surface waves. However, 
about 1800, 1 could "hear" or distinguish the pressure fluctuations associated with the passage 
of surface waves. This was verified by topside watch officer. This p.m. was the last time I 
was able to "hear" the pressure change of surface swell. This is probably because of bad hear- 
ing caused by humidity and ear infection ( ?) or low waves. 

5th Day 

In the a.m. net current drift was offshore, very mixed and erratic, from high waves on the 
surface last night ( ?). Plankton move offshore and sink most of the time. Same condition pre- 
vailed all day, current strongest at dark or about 1800. One observation at 2200 shows slight 
offshore current, plankton sinking down. Low waves, no surge, just steady offshore. Visibility 
was very good today, and there was no indication of high waves. 

6th Day 

Wind chop on surface following 8-10 ft swell reported at surface. 0800— no current; 0900— 
slight current flowing to the north and onshore about 0.1 knot; 1000— current increasing, surge 
has on and offshore orbital motion, net drift onshore, orbital diameter 4-6 in.; 1030— current 
increased, net displacement of 4 in. onshore during each cycle of the orbit; 1045— steady on- 
shore or northern drift broken by irregular periods of 10-12 sec of offshore surge. Net is on- 
shore about 15 in. in 15 sec. All offshore motion is erratic. Note: Fish (scorpion or Scorpina 
Gattata) orient into the current, as a rule, unless feeding or moving which is about two to four 
times a day. Other small fish, 1/2 cm-1 cm long, and some large migratory fish have no ob- 
vious orientation preference so far as current direction is concerned. 1057 — slight onshore net 
drift. 



UNDERWATER WEATHER STATION 383 

Set five plastic bottom drift indicators outside. In 20 minutes they had drifted downslope 
10 ft. Net drift of sediment is also downslope. A steady current, enough to clean off large ob- 
jects on the bottom, is evident. A 35-pound Danforth anchor on the sand slope has been ex- 
posed for two days. Water temperature is 13.5°C, well mixed down to 230-ft depth. 

1600— Very steady up and onshore current. Plankton moves 24 in. in 12-15 sec; 1730— 
current changed to offshore, 24 in. in 13 sec; 1800— current is onshore, changed direction 
very quickly. 

Visibility reduced considerably today following wind waves. Heavy red tide this p.m. 
Sundown at 1900. Visibility 2 ft with hand-held light. 

7th Day 

Mixed current— short on and offshore surge. Plankton moves 24 in. in 20 sec. Heavy red 
tide last evening, came down fast from seaward. Heavy watch day. Very slight onshore cur- 
rent all day. Red tide sinking to sea floor. 

8th Day 

Little current detected from ports. Fine plankton in early morning drifting down and 
slightly offshore— visibility bad. By mid-morning, water became very clear, the clearest wa- 
ter we have observed, 30 ft visibility with natural light. Worked locating underwater weather 
station. Anchored weather station platform. 

1800— visibility bad again, more red tide. Visibility changed quickly. Plankton moves 24 
in. in 21 sec with offshore net drift. Continuous offshore flow with slight fluctuation in veloc- 
ity. 1800-dark. 

9th Day 

Dense red tide. Fish fill the ports, making current observations difficult. Slight offshore 
and down net drift. Clouds of sediment rise 5 ft above the bottom from divers working on the 
weather station. Drift is slow to clear sediment from the area. Set underwater weather plat- 
form today. 

10th Day 

Temperature 13.5°C, warm. Visibility bad. Slight offshore current, plankton sink slowly. 
Trajectory is 8 sec down, 8 sec off, 8 sec down, etc. Net offshore, 8-9 in. in 16 sec. Steady 
temperature increase for three days, 46-48-50-55°F. 

1100— short periods of up and offshore current. Net transport offshore and down, 2 ft in 15 
sec. Mid-afternoon to dark— trajectory of plankton shows the following periodicity in cycle: (a) 
horizontal offshore movement for 8 sec, followed by (b) up movement for 8 sec, etc. The net 
drift is offshore and up. 

nth Day 

Upper direction vane (1) and Savonius rotor (2) on weather station in operation. Rustrak 
recorders in Sealab are recording. Recorded current of 0.8 knot. During diver inspection, 
sensor 2 turning one revolution in 2 sec and direction vane indicated current flow offshore. 
Sensor 5 turning one revolution in 4 sec. Analog record of sensor 2 indicates 0.1 knot steady 
during day, increased at 1700 to full scale (almost 2 knots) on the upper current sensor (2) and 
to 1 knot on the lower current sensor (5). Current direction offshore. 



384 UNDERWATER WEATHER STATION 

12th Day 

Lower weather station out of order in a.m. Upper weather station appears o.k. Installed 
thermistors— upper temperature 53°F (11.5°C), lower temperature 51°F (10.05°C). 

Sensors 1 and 2 indicate 0.5 knot offshore current; observations from Sealab port indicate 
24 in. in 25 sec offshore. Decreased to "0" current by 1200. Plankton sinking down steadily. 
1700— observed very slight offshore and down current. 1800— same observation, 24 in. in 30 
sec. Temperature at 1600 was 55°F (12.2°C) with thermometer hand held outside. Thermistor 
records 51°F (10.05°C) on line 36 of Rustrak recorder. 

13th Day 

Temperature 50-51 °F (thermistor o.k. with hand-held calibration). Visibility poor due to 
plankton. Current— 0.2 to 0.6 knot on sensor 5. Direction vane shows offshore flow most of 
day. Current observations from Sealab port: 

0800 offshore and down 

1030 offshore and down 24 in. in 40 sec 

1100 offshore and down 24 in. in 60 sec 

1200 sinking down very slowly 

1600 current changed to up 24 in. in 30 sec 

14th Day 

Visibility poor in early a.m. Current upwelling— up and offshore 6 in. in 20 sec. 1100— 
sensor 5 indicated 0.35 knot steady. Sensor 2 (upper) off scale on high side. Current direction 
southwest to south southwest. 1145— Sensor 5 reads 0.3 knot, sensor 2 reads off scale on high 
side. Current direction southwest. Flying fish came in with upwelling? Sediment covers rotors 
in three-day period. Mica and light material deposit on flat surfaces. Thirty-five pound anchor 
covered by sediment. One-quarter in. sediment fill on underwater weather station platform in 
three days. Sensor 5 is dirty; sensor 2 is clean and runs faster than 5 on all observations. 

15th Day 

Visibility very poor, no light. Many fish at the ports. Current is offshore and up, no surge. 
Very slight current. Good weather topside for transfer of personnel. 



Diver observations and their comparison with the underwater weather station recordings 
show a fluctuating irregular current pattern during periods of high waves. This is followed by 
a somewhat more uniform flow during periods of low waves. 



Chapter 42 
SEALAB II SALVAGE TESTS 

W. F. Searle, Jr. 
Naval Ship Systems Command Headquarters 
Washington, D. C. 

INTRODUCTION 

In addition to making his West Coast salvage ship, USNS Gear (ARS-34), available to sup- 
port the operation, the Supervisor of Salvage, U.S. Navy, sponsored a number of ship-salvage 
oriented projects in Seal^b II. The general objectives of the several tasks were: 

1. To demonstrate the feasibility of conducting long-term salvage operations from a bottom 
habitat. 

2. To determine the capability of divers to accomplish strenuous salvage work during pro- 
longed saturation dives. 

3. To perform subjective in situ tests and field evaluations of several new or modified tools, 
systems, and techniques in 205 ft of water. 

4. To determine the feasibility of scuba- equipped divers to use these tools in deep water, 
versus hard-hat equipped divers. 

The general objectives were accomplished with considerable success. All assigned tasks 
were performed during Team 3's tenure on the bottom. Diver tasks in general were performed 
with dispatch and skill, and consistently in less time than had been programmed. It was clearly 
demonstrated that the saturated diver, as a man, could handle the tools employed and accomplish 
the tasks assigned. This is not, however, to say that the tools in each case were optimum. Nor 
can it be said that all diver-support systems were satisfactory. On the contrary, the lack of 
adequate diver-to-diver and diver-to-topside communications, and the inadequate body-heating 
systems hampered the divers in the accomplishment of their tasks. That they nonetheless were 
able to perform satisfactorily further emphasizes the feasibility of scuba-equipped saturated 
divers, operating from a bottom habitat, performing typical complicated, strenuous salvage 
tasks. 

In the following sections each of the several salvage tasks and tools will be described. 

FOAM-IN-SALVAGE (FIS) 

The Foam-in-Salvage (FIS) tasks were included in order to test a new salvage technique. 
The use of cast-in-place, frothing foams had previously been employed in salvage only in 
shallow depths, no deeper than 30 ft. The FIS project in Sealab 11 was oriented toward demon- 
strating the use of this technique for imparting controlled or fixed buoyancy (as opposed to air 
bubbles, which migrate) to complicated structures underwater. An aircraft hulk was selected 
as the principal test bed. It is easy to think of this as a missile, a space capsule, or a sub- 
marine. The Sealab II tests were particularly important in the BuShips FIS program in that 
they permitted a realistic test of the system (Fig. 145) at depth and at low ambient tempera- 
tures. Laboratory tests at these depths and temperatures had not been especially realistic. 

As stated, the principal test bed was an F-86 jet aircraft hulk which had been made avail- 
able to the program by the Bureau of Naval Weapons. The wings and most machinery had been 

385 



386 



SALVAGE TESTS 



„ ,. Mixing 

No22le,5x| OD(f ID) chamber 



Gun 



Controller 




operated by trigger 

Check valves 

Manuolly operoted 



i hose- 



solvent valve 



Strainer 




Stondpipe 



y) Regulator 
Nitrogen 



{ 



--I hose 



Strainer 



Safety 
^^ valve 



Nitrogen 




Standpipe - 



Safety 
valve 

-IE 



Nitrogen 
Catalyst 



Note. Valves on ^ hoses normally open A-52779 

Fig. 145. Schematic diagram of Sealab II foam-in-place equipment 



removed. The hulk was made heavy with cement ballast, and a series of holes was placed in 
the fuselage. A circle was painted around each hole to guide the diver. Each hole was marked 
with a "time-in-minutes to foam," based on the volume of the compartment and the expected 
foaming rate. The hole times varied from two minutes to 18 minutes. 

In addition to the aircraft hulk, nine empty ordinary 55-gallon oil drums were prepared with 
cement anchors and placed on the bottom. The drums were to be foamed and raised, singly, 
over a period of several weeks, in order to study the amount and rate of water absorption (i.e., 
loss of buoyancy) by the foam. 

The technical aspects of the FIS project are reported in detail in the final Foam-in-Salvage 
Report submitted by the Murphy -Pacific Marine Salvage Company, (Final Technical Report- 
Contract Nobs 4909 dated 7 May 1965), and will not be discussed here in detail. It will suf- 
fice to say that the chemical formulation of the foam used in the Sealab II Salvage Project 
was less than optimum. Additional testing and formulation was indicated and has, since Sea- 
lab n, been undertaken by Murphy-Pacific and BuShips. 

Notwithstanding the less-than-optimum foam, it must be concluded that the Sealab II FIS 
project was quite successful in demonstrating the feasibility of such a salvage system. One of 
the key features of the project was the demonstration of a system which required a considerable 
degree of coordination between the divers on the bottom, handling the foam gun and applying the 
buoyancy, and the surface -support ship (Gear) with its source of bulk chemicals and mixing and 
hose delivery apparatus. The total lack of diver -to -surface communications was particularly 
difficult to cope with. An adequate diver-to-surface communication system would be an essen- 
tial requirement in an FIS operation of any magnitude. 

Sealab II divers experienced no difficulty in handling foam guns and hoses; nor was there 
any difficulty in inserting the gun barrel into the prepared holes in the aircraft hulk, or into the 
oil drums (Fig. 146). Gun application (triggering and flushing) presented no problem (Fig. 146). 
These evolutions were easily learned in one preliminary session before Team 3 was developed. 
The evolutions were easily executed until the diver became overtaken by cold. 



SALVAGE TESTS 



387 




a. Foam in salvage (FIS) gun ready for foaming 



#^«^^^ 


^p 


1 

. .. Jk 


^ 


I^> 


'^^h 




b. FIS gun ready to load foam 
in test barrel 



d. Model D stud driver trigger fired, push- 
button barrel safety, spoil shield and will 
not fire at more than 8-degree angle 



e. MSA wire cutter for 
3/4-inch wire rope 





f. Ten-ton velocity- 
power lift pad 



c. Model D stud driver penetration 
through HY-80 plate 





g. Ten-ton lift pad with 
two holding magnets 



Fig. 146. Sealab II salvage tools 



The aircraft hulk was foamed first. Two divers were employed in the foaming process 
(Fig. 147). The divers commenced foaming at the tail. They then foamed holes in the fuselage's 
side, and the hulk soon floated free, 10 ft off the bottom, tethered by wire-rope pendants to its 
cement-clump anchors. Once the hulk floated, the foaming was stopped, even though the quantity 
of foam delivered (time of application) was much less than had been calculated to be required. 
This early cessation of foam application proved to be an error which may be attributed to lack 
of communications and to cold divers, anxious to "go home" to Sealab. 

The foamed aircraft hulk, after several hours, was inspected by surface divers and found 
to have settled to the bottom. It was, however, found to be "light and lively;" that, is, it was 
only slightly negatively buoyant. The next day, the aircraft hulk was "foamed" again by Sealab 
divers. The evolution was essentially the same as the previous day. Again, the hulk floated 



388 



SALVAGE TESTS 



l^k 




ifc 






s; 



Fig. 



147. Aquanaut P. S. Wells uses the foam-in-salvage gun 
to foam an aircraft hulk near Sealab II 



quickly and foaming was stopped. The total foaming time (raw materials used) was still short 
of that which had been calculated to be required to fill the aircraft. 

The hulk was scheduled to be raised on the following day, anchors and all. When surface 
divers inspected it they found the hulk again on the bottom, again "light and lively." Gear's 
hoisting wire was attached to the hulk's lifting bridle, and the aircraft with anchor clumps 
attached was raised and placed on deck. 

Upon inspection of the hulk, it was found that several holes had not been foamed. In partic- 
ular, the aircraft's air-inlet cowl, in its nose, had been overlooked. This compartment was the 
largest single compartment in the hulk, and 18-minute hole. Evaluating the quantity of foam 
applied, and taking into account that the foam itself was of poor quality, it was concluded that 
each time the hulk floated it was "just" buoyant, and that the amount of positive buoyancy impar- 
ted was but a small proportion of total weight of either the hulk or the foam applied. Thus, a 
slight amount of total water absorption could cancel out the positive buoyancy. It may be con- 
cluded that when using FIS, the total foaming operation (as engineered and planned) must be 
carried out. So long as the total system— including the buoyant body and its tether and achors— is 



SALVAGE TESTS 389 

negative, all planned buoyancy should be installed* The tendency of divers to want to quit once 
the body has floated should be resisted. The Sealab II divers had not been so instructed. Pos- 
sibly had the foam been of better quality, we would not have learned this rudimentary point so 
quickly. 

The several oil drums were foamed successfully and without incident. All floated to their 
tethers. The fact that they did not sink again, like the aircraft, is indicative that they were 
"over-foamed." The small size of the drum required that the diver foam for only about a min- 
ute. It was almost impossible to "under-foam." Also the drums, being totally enclosed except 
on their bottom, presented very little wetting surface for water absorption. 

It has been mentioned that the foam was of poor quality. As the foam chemicals were ap- 
plied by triggering the gun, the exothermic reaction took place, but the freon gas, used as the 
frothing agent, was not effective. The partial pressure of the freon gas at the depth and tem- 
perature of application was too close to ambient depth pressure. The gas did not consistently 
froth. The foam was too dense and had poor shear characteristics. It appeared that the initial 
shot of each application did not foam at all, until the exothermic reaction got "heated up." This 
initial amount of unfrothed foam material quickly solidified as a ceramic-like mass. In at least 
one instance, it covered the divers' Mark VI breathing apparatus, and completely fouled their 
breathing bags and exhaust valves. The danger is obvious. 

So far as the Sealab II FIS demonstration is concerned, the project is considered to have 
been quite successful. It was clearly demonstrated that divers, at a dept of 205 ft, could handle 
the foaming equipment. It was also demonstrated that a diver-topside evolution could be per- 
formed, even without communications. The salvage engineering lessons learned were particu- 
larly worthwhile. The foam itself was, without doubt, disappointing. In fact, the foam was an 
order of magnitude less satisfactory than had been obtained during preliminary deep tests held 
in San Francisco Bay. 

VELOCITY POWER TOOLS 

Velocity power tools which utilize the energy from an ammunition-type cartridge to drive 
threaded solid and hollow studs into and through steel plates have been used by divers since the 
late 1930's. However, because of several accidents during World War II and the unavailability 
of parts, these tools fell into disuse in the Navy. Prior to Sealab II, few active divers had any 
experience or appreciation for the utility of these tools. The purpose of the tests covered here 
was twofold: (a) to demonstrate the utility of the tools as applied to scuba divers in 200 ft of 
water, and (b) to demonstrate an attachment padeye concept which might be used in submarine 
salvage. 

The single-stud driver (Fig. 146) was an improved experimental model developed by the 
Mine Safety Appliance Company of Pittsburgh, Pennsylvania, under contract to the Naval Ord- 
nance Laboratory, White Oak, Maryland. The wire-rope cable cutter (Fig. 146) was an older 
and proven design. The improvements in the single-stud driver in general provided for pene- 
tration into various thicknesses of HY-80 steel plate. Other improvements enhanced diver 
operability and safety by better containment of the explosive gas energy. This last improve- 
ment reduced the shock on divers to negligible proportions. However, the single-stud driver 
still must be fired with the head of the diver held out of the line of sight, to prevent shock load- 
ing on the eardrums (Fig. 148). One aquanaut learned this in a painful trial shot, fired in a 
shallow pool prior to Sealab II. The eight-stud lifting pad array was the prototype of a new 
design, prepared under contract to NOL. 

All tool performance was satisfactory, with the exception of the cable cutter. The latter 
was never successfully fired because of a defective "o" ring seal. The other prototype devel- 
opment models performed well with only three duds out of 15 shots attempted. 



*The on-going BuShips/ Murphy-Pacific contract addresses this engineering problem. The sal- 
vage engineer must know how miuch water absorption— both as to rate and quantity (lost buoy- 
ancy) —to allow for. 



390 



SALVAGE TESTS 




Fig. 148. Aquanaut Meeks fires explosive stud into simulated 
submarine hull near Sealab 



The ten-ton lifting pad (Fig. 146) was successfully attached to a one-thick HY-80 steel 
curved mock-up of a submarine hull section (Fig. 149). Also, a flat, mild steel patch and gas- 
ket was bolted to the threaded studs driven into this mock-up with the single-shot tool (Fig. 146). 
The lifting pad was tested on site by the aquanauts using the 8.6-ton collapsible Sealdbin pontoon. 
Structural tests of the pad array were later conducted at Long Beach Naval Shipyard following 
Sealab n. The patch was also tested hydrostatically. 

At the shipyard the padeye device was successfully loaded to 10 tons in all axes without any 
evidence of studs pulling free. The device was then tested to destruction. The array's plate 
failed where the padeye swivels. No studs failed. The flat plate patch tested satisfactory to 
15 psi hydrostatic pressure without stud slippage. 

From a subjective standpoint, all the tools were easily handled and performed to the gen- 
eral satisfaction of the divers. 

The results of these tests lead to the conclusion that further development and eventual use 
of these tools by the salvage forces is warranted. This development should include further con- 
tainment of shock from the single-stud driver and increased penetrating capability for our heavy 
submarine hulls. The shipyard tests on the padeye indicate need for redesign of the structural 
part of the device.* 



*The Bureau of Ships, in support of the DSSP program, and with BuWeps concurrence, in sup- 
port of the DSSP program, has assigned a task to NOL White Oak for the further development 
of these tools. On-going contracts have been let to MSA by NOL. 



SALVAGE TESTS 



391 




Fig. 149. Aquanaut Meeks fires explosive stud into patch on 
simulated submarine hull near Sealab II 



COLLAPSIBLE SALVAGE PONTOON 

The collapsible 10-ton* salvage pontoon is a modified version of U.S. Rubber Company's 
Sealdbin rubber container used to ship bulk quantities of liquid and granular materials. The 
off-the-shelf container, with minor modifications, makes an excellent salvage pontoon. 

The purpose of these tests was (a) to evaluate the ability of divers to manhandle the col- 
lapsed pontoon and to manipulate pontoon hardware when submerged, (b) to test new quick- 
disconnect fittings for attaching the air hose, and (c) to demonstrate a venturi system of pontoon 
evacuation to obviate the need for having to pull the pontoon down or weight it down at the start 
of submergence. 

The pontoon successfully lifted the submarine mock-up assembly; however, the divers had 
considerable difficulty in manhandling or maneuvering the pontoon on the bottom in a collapsed 
condition. The negative buoyancy in the collapsed (bottomed) state was approximately 250 lb. 
The pontoon presented a large, cumbersome, and nonpliable package. The quick-disconnect 
fittings were found to be too difficult to operate in the cold water. In addition, the female fitting 
on the pontoon for attaching the blow vent hose leaked. A later examination revealed that this 
female fitting cannot be properly lubricated without removing it from the pontoon— a time- 
consuming maintenance task. The venturi topside evacuation procedure worked quite satisfac- 
torily. 



''The pontoon is classed nominally at "10 ton. 
ity of 8. 6 tons. 



In salt water, it has an actual buoyant liftcapac- 



392 



SALVAGE TESTS 



ii was concluded that the collapsible pontoon has the potential of being a versatile and use- 
ful salvage device. However, account should be taken of the difficulty experienced by divers in 
handling this unit. Elimination of minor hardware discrepancies will make the ten-ton pontoon 
a very useful item in the salvage inventory. 

Investigations into the optimum pontoon capacity should be initiated for representative sal- 
vage operations. Clusters of pontoons could provide a lift capability which might be quickly 
transported to any corner of the earth. Lift control could be provided by arranging balloons at 
various depths. Problems associated with this concept should be investigated.* 

PNEUMATIC -POWER ZERO-REACTION HAND TOOLS 

To make a man-in-the-sea more effective, he must be provided with powered tools designed 
for his capabilities and the environment which limits his normal surface abilities. 

Since no powered tools had been designed to fill this need, the Battelle Memorial Institute, 
Columbus, Ohio, conducted preliminary underwater tests in a test pool and in a water-filled 
gravel pit with commercial pneumatic zero -reaction production tools which were modified 
specifically for diver use. The promising results of these tests led to the development of an 
ocean-bottom experiment which was conducted by the aquanauts at Sealab II, at no expense to 
the Navy. 

This experiment included the use of a "reactionless" impact wrench and related test stand 
(Fig. 150). Also, a pneumatic hammer was modified to drive a coring device of simplified de- 
sign into the ocean bottom. The impact wrench was used to drill and tap holes, run nuts and 
bolts, and for hole-saw cutting. 

The modified tools, which were adaptations of tools designed for the surface, did not per- 
form all of their functions as well underwater. This reduced performance capability had been 
anticipated, and some of the causes are readily understandable; however, other aspects will 
require further study. The initial operation of the tools was degraded'fcomewhat by two defec- 
tive hose couplings. "*# 

The combined effects of depth, near-zero visibility, low temperature, and gas-flow noise in 
the breathing apparatus masked the feedback of intelligence to the operator necessary to exert 
proper control over lightly loaded functions such as thread tapping and drilling. The reaction, 
vibration, and noise from the impact wrench was so slight that feedback could be felt only when 
the tool was triggered initially for each function, as in final nut and bolt torque up, and while 
hole-saw cutting. As an example, while drilling, the aquanaut could tell that the tool was work- 
ing only by closely observing the metal cuttings produced. Perhaps the tools were too reaction- 
less. Feedback intelligence of some type is clearly necessary. 

An interesting result of drilling underwater is that it was learned that center punching is 
unnecessary for drills 3/8 in. or larger. With 1/4 in. and smaller drills, the same technique 
could result in rapid wear of the drill tip. 

The pneumatic -hammer-driven bottom -coring device performed very satisfactorily. Four 
cores were obtained around the base of the Sealab in less than six minutes. 



*BuShips has adopted this pontoon, with several improvements, as a Standard Emergency Ship 
Salvage Material Pool item. The improved pontoon has the added feature of being sufficiently- 
strong to permit tiering three high in a lift mode. 

■fBuShips, with BuDocks concurrence, has assigned the Naval Civil Engineering Laboratory, 
Port Hueneme, California, as "lead lab" for the development of collapsible pontoons in support 
of the DSSP project. NCEL has let an on-going contract with U.S. Rubber Company for the 
adaptation of the larger commercial Sealdtanks (up to Z5 tons lift capacity) for use as salvage 
pontoons. This project looks to the possible use of larger collapsible pontoons in place of the 
current 80-ton structural submarine salvage pontoons. 



SALVAGE TESTS 



393 




Fig. 150. Aquanaut Reaves tries out underwater tool test 
stand on the Sealab II surface support vessel 



The aquanauts were impressed with the tool performance and the possibility of obtaining 
suitable tools for their normal underwater work. Many excellent suggestions were received 
from them on ways to improve the tools. These encouraging results appear to warrant further 
development of tools designed specifically for the underwater worker in his demanding environ- 
ment. 



Chapter 43 
THE BENTHIC LABORATORY 



V. C. Anderson 

Marine Physical Laboratory 

San Diego, California 



The benthic lab, as used with Sealab II, is shown in Fig. 151. It is an unmanned, remotely 
operated electronics complex housed in an oil-filled inverted dome, or "hive", mounted on the 
sea floor near the Sealab habitat. This complex is connected through a single coaxial cable to 
the benthic control console, one mile away on shore. 




Fig. 151. The benthic laboratory prior to its 
placement at the Sealab II site 



In addition to control and monitor functions associated with the operation of the benthic 
lab, the electronics provides for the multiplex and demultiplex of quite a number of television 
video, audio communication, and digital telemetering channels to and from Sealab over the 
single coax to shore. The ac power required to operate the benthic lab is also transmitted 
over the same coaxial cable. 

The transmission system provides for the transmission of 36 audio communication chan- 
nels, with a nominal 5-kHz bandwidth: 12 channels from shore to benthic, and 24 channels from 
benthic to shore. Additional provisions are made for the transmission of five simultaneous, 



394 



BENTHIC LABORATORY 



395 



5-MHz bandwidth TV video signals from benthic to shore. The time -multiplex telemetering 
system provides 128 channels in each direction with a 60-Hz sampling rate on each channel. 

The benthic hive is filled with optically clear acid -washed kerosene. The interior is 
lighted by 16 lights which are turned on individually and in pairs via the shore -to-benthic time- 
multiplex channels. Two television cameras with remotely operated pan/ tilt capability are 
located inside the hive and provide vision for inspection and servicing of interior electronics. 

All circuits are made up on plug-in cards and are contained in 22 modular assemblies 
arranged in a ring around a mechanical manipulator which is operated remotely over the time- 
multiplex channels. The ring assembly is shown in Fig. 152. There are spare circuit cards 
for all critical circuits stored in the modules for easy access by the manipulator. Other fea- 
tures include manipulator -actuated switches, both rotary and toggle, and an instrumentation 
patch panel where any one of over 70 voltages and waveforms may be selected for telemetering 
to shore for system check or trouble shooting. 




Fig. 152. The benthic laboratory modular assemblies ar- 
ranged in a ring around the mechanical manipulator 



A completely independent backup telemetering system, providing 24 channels for critical 
control functions such as manipulator, lights, and TV, could be placed in service for trouble 
shooting in the event a failure should occur in the primary system. 

A pair of hydrophones are mounted, one on each side of the manipulator. The hydrophone 
outputs are transmitted to shore for stereo listening in order to give the operator an additional 
sense of certain operating conditions which would not otherwise be available. 

The operation of the benthic lab is carried out from the benthic control room located on 
shore. Fig. 153 shows the configuration of the operators' console. 

The initial attempt at manipulation within the benthic hive was carried out on Sept. 1, the 
day after the emplantment of the benthic lab. The attempt was made using benthic TV camera 
2, located between modules 22 and 23, near the TV modulator cards in module 21. This par- 
ticular TV camera appeared to be faulty, and the picture definition was very poor, indicating 
either an oil leakage into the optics or a faulty electromagnetic focus circuit. A comparison of 



396 



BENTHIC LABORATORY 




Fig. 153. The benthic laboratory operator's con- 
sole at Scripps Institution of Oceanography 



resolution of the two cameras is made in Fig. 154. The vertical and radial position of the 
manipulator was first established by use of camera 1 on the opposite side of the hive, then the 
manipulator was rotated into the field of view of camera 2. After a considerable number of 
trial approaches the manipulator hand was engaged in the card slot of one of the spare modula- 
tor cards, and the card was extracted from its slot. The card was moved down to video 6 mod- 
ule slot and successfully inserted. The engagement of the pins was indicated by the occurrence 
of a strong interference pattern on TV channel 2. The card was then removed from this slot 
and an attempt made to return it to the storage slot in its original location. At this point con- 
siderable difficulty was encountered in aligning the card with the slot as a result of the poor 
definition of camera 2. In the process of manipulation the card was dropped and lost from view. 
A cursory examination of the hive with camera 1 did not disclose the final resting place of the 
card; however, a more careful examination late that night revealed the card might be lodged in 
the cable harness near the terminal block area (Fig. 155). Recovery of the card was considered 
but the complete lack of visibility of this area from the camera 1 vantage point made it virtually 
impossible, and no recovery attempt was made. 

The following day the hydraulic system was checked in an effort to determine the cause of 
the accidental release of the card from the manipulator jaws. The integrity of the hydraulic 
lines was investigated by listening to the cavitation of the hydraulic pump through the monitor 
hydrophones and energizing the negative-pressure solenoid for the various functions intermit- 
tently. If the pressure had remained the same in the circuit during the interval of time the 
solenoid was closed, the flow through the pump would not be changed upon reactuation of the 
valve. However, if the pressure had relaxed in the circuit, the reduction in pressure when the 



BENTHIC LABORATORY 



397 




Fig. 154. Comparison of the resolution of the two benthic laboratory TV 
canaeras. The poor resolution of camera 2 was caused by either oilleak- 
age into the optics or a faulty electromagnetic focus circuit 




Fig. 155. Benthic labora- 
tory terminal block area 



valve was connected across the manifold would be accompanied by a reduction in the cavitation 
noise. This reduction of sound was observed on the grip hydraulic circuit after a few seconds 
delay, indicating the presence of a slow leak in the system. In future manipulations this fact 
was taken into consideration by periodically re -energizing the grip solenoid whenever the grip 
action was used. 

The next manipulation effort attempted was the use of the patch panel to check the perform- 
ance of the amplitude -modulated communication links. In this operation camera 1 was used. 
Its location between modules 8 and 9 gave an ideal vantage point for the operation on the patch- 
panel board located in module 12. The manipulation was successfully carried out and involved 
the transfer of both ends of the patch cord. One end was moved to the monitor jack on the up- 
per half of the panel from its original position in the monitor jack on the lower half of the panel 
(Fig. 156). The other end of the cord was then inserted into the desired jack in the panel (Fig. 
157). The jack numbers were marginally readable in this particular area, which was in the 
upper third of the bottom half. The location of the jack was confirmed by counting the jack 
sequence from a readable number at closer range. During the checking operation it was also 
necessary to operate the range. During the checking operation it was also necessary to oper- 
ate the rotary switch in the center of the patch panel (Figs. 158, 159). In one position of the 
switch, the detent could not be overcome by the wrist-rotate motor torque alone, and thus it 
was necessary to stall the wrist-rotate motor and then operate the arm-rotate motor to obtain 
increased torque. Although both functions are driven from identical motors, the loss in the 
compound gear transmission link, including the worm-gear final reduction of the hand-rotate 
function, gives rise to a lower stall torque than the spur-gear reduction of the arm-rotate 
function. 



398 



BENTHIC LABORATORY 





Fig. 156. Benthic labora- 
tory plug -in monitor jack 
of patch panel 



Fig. 



157. Plug -in jack 
number 59 





Fig. 158. Benthic labora- 
tory manipulator hand ap- 
proaching monitor switch 



Fig. 159. Benthic labora- 
tory manipulator engaged 
in monitor switch 



The major difficulty which was encountered in working with the patch panel was that of 
releasing a patch-cord plug handle once the plug was engaged in its socket. It was somewhat 
ironic that it at times appeared to be impossible to release the patch cord without pulling the 
plug from its socket, even though several times during the operation the plug nearly fell off 
the hand while maneuvering it outside of the socket. It is apparent that a more satisfactory 
method of engaging objects to be maneuvered is required. 

The capability of monitoring the circuits in benthic is a powerful tool in the benthic lab 
operation. Using this patch panel it was possible to determine the total effect of oil immersion, 
temperature, and pressure on the tuning of three of the receivers and to retune the oscillators 
in the surface-operating equipment to match the final receiver frequencies. It became appar- 
ent that it would be desirable to have even more system voltages and waveforms brought out 
to the patch panel. In particular, if the voltages of the TV cameras had been available, it would 
have been possible to determine the cause of the malfunction of camera 2. Also, if all receiver 
outputs were brought out, a complete system alignment could be carried out. 

The first major effort at card replacement in benthic was undertaken on Sept. 23, in an 
attempt to rectify difficulties encountered with the analog -to -digital converter digital trans- 
mission link (see Chapter 21). On the previous day, measurements taken in Sealab had indi- 
cated an abnormality in data channels 7, 8, and 10. At 10 a.m. on Sept. 23, the manipulator 
was engaged in the diode matrix card which was located at the extreme bottom of module 3 



BENTHIC LABORATORY 



399 



(Fig. 160). The card was extracted part way and released from the manipulator, leaving it 
disengaged from the connector but still in its slot. The operation took approximately 45 min- 
utes. A second check of the voltages on the analog -to -digital converter-card socket showed 
that the anomalous voltage readings still existed on channels 7 and 8. Following this test, 
Sealab was requested to disconnect the plug at the rear of the electronics rack so as to permit 
measurements to be made on the cable itself. At this point the operations were interrupted by 
preparation for a dive by the aquanaut assisting in the test, Art Flechsig. 




Fig. 160. Benthic labora- 
tory location of faulty card 
(bottom of module 3) 



Anticipating that the diode matrix card could be faulty, the manipulator was once again 
engaged in this card, and the card was removed from the slot. The card was brought up close 
to the TV camera and inspected visually for physical damage, particularly any damage to the 
card pins. No evidence of physical damage was observed. The card was then moved to a 
vacant slot in module 4 and partially inserted. Fortunately, before the card was plugged in 
completely, an operator recalled that the particular vacant slot was not a storage slot, but was 
a spare SCR driver card slot, completely wired, with 110 v ac appearing on the pins. The card 
was immediately removed from this slot, and a storage slot was located at the top of module 
11. This slot was in a very good vantage point from the TV camera, and no difficulty was ex- 
perienced in storing the card in this position. 

During this interruption an attempt was made to use the manipulator to move camera 1 to 
a new location. The engagement slot for the manipulator fingers is located half way down on 
the lift bracket, in a position which is completely blind from either camera. In order to pre- 
pare the camera for lifting it was first necessary to rotate the lift bracket from its stored 
position at the side of the camera to the forward position. This was accomplished by wedging 
the fingers between the bolt heads at the top of the bracket and the camera body (visible in 
Fig. 154) and rotating both the wrist pivot and the manipulator rotate function to swing the 
bracket out into position. The wide range of focus provided in the cameras permits the oper- 
ator to focus on this operation, which takes place only a few inches from the camera lens. 
Once the lift bracket was rotated into the forward position, the manipulator was retracted into 
the field of vision of the camera and the arm realigned with the wrist pivot axis vertical, the 
fingers rotated to the horizontal position, and the wrist pointed directly outward in the radial 
direction. The fingers were then brought up to the top of the lift bracket to obtain a reference 
measurement on the vertical scale provided on the manipulator. While observing the vertical 
scale, the arm was dropped 10-3/16 in. and brought into contact with the lift bracket. The 
manipulator was positioned so as to maintain a slight pressure on the bracket, and the hand 
was then moved up and down until the lifting slot was located by "feel." After locating the slot, 
the manipulator was extended to fully engage the slot, the jaws opened, and the manipulator 
rotate jogged to center the fingers in the slot to permit full engagement. With the jaws locked 
in the slot, the TV camera mirror was tilted through the axis of the camera to observe the 
rear attachment to the module, and an attempt was made to lift the camera from its support 
hook. The attempt was unsuccessful. Although it was possible to raise the camera, it was not 
possible to clear the hook or fully support the camera by the manipulator hand. Apparently 
either the clamp action was not strong enough or else the grip-function hydraulic leakage was 



400 



BENTHIC LABORATORY 



too great to maintain the jaw engagement in the slot. After it was apparent that the camera 
would not lift free of the support hook, the mirror was rotated back to observe the manipulator, 
and the manipulator was found to be retracted out of contact with the lift bracket. In view of 
the extremely high risk of dropping the camera under this type of operation, further attempts 
to move the camera were suspended. Approximately one hour was spent in working with the 
camera in this attempt to reposition it. 

At 1230 the aquanaut was available once more to resume testing, and a check of the cable 
at this time indicated that the voltage previously measured on channels 7 and 8 was not present. 
The plug was re-engaged, a second check made of the voltage at the A to D card socket, and 
the absence of the voltages confirmed. 

At this point the remaining task was to extract the spare card from its position in module 
3, five slots down from the top, (Fig. 161), and insert it into the bottom slot in the same module 
from which the faulty card had been removed. Unfortunately, the vantage point of the camera 
for the upper slot of module 3 was poor, in that the fingers were hidden by the manipulator 
body. Accordingly in order to extract the card it was necessary to position the manipulator 
vertically with reference to the fifth card down in module 4 and time the traverse from corre- 
sponding points on modules 5 and 4 until a reproducible traverse could be made by timing. The 
traverse was then timed from the center of the card handle on module 4 to the supposed position 
of the card handle on module 5. At this point, the manipulator was extended until contact with 
the card handle was indicated by a slight shift in the position of the module, and the raise-lower 
function was jogged until the jaws engaged the slot. Next, the manipulator was extended to stall- 
out, following which it was relaxed slightly by again observing the motion of the module. With 
the jaw-open solenoid actuated, the manipulator rotate function was jogged to center the hand 
in the card handle. By retracting the manipulator slightly, the jaws engaged the notch and 
locked onto the handle. The card was then extracted. During extraction, the proper alignment 
of the manipulator was determined by observing the card deflection and jogging the manipulator 
vertically and radially as indicated to align the card with the slot. Throughout the entire trans- 
fer operation the jaw -open solenoid was actuated every two to three seconds to be sure that 
the card would not accidentally be released. While transferring from the number 5 slot to the 
bottom slot of the module, the wrist was rotated in an upward orientation so that the card 
could not accidentally drop from the jaws. 

Considerable difficulty was experienced in replacing the card in the bottom slot. Visibility 
conditions were quite poor, in that the lighting at the bottom of the module was inadequate for a 
sharp TV display (Fig. 162), and the use of only one camera made it very difficult to estimate 
distances or orientation of the card at the bottom of the module. A number of tries were re- 
quired before the card was finally engaged in the slot. Although an accurate measurement of 
time was not kept on this operation, insertion of the card in this slot required about 20 minutes 





Fig. 161. Benthic labora- 
tory slot from which spare 
diode matrix card was ex- 
tracted 



Fig. 162. Benthic labora- 
tory manipulator in posi- 
tion to engage bottom card 
of module 3 



BENTHIC LABORATORY 



401 



compared to tJie two or three minutes required for inserting the faulty card in the top slot of 
module II where visibility conditions were ideal (Fig. 163). The card was successfully inserted 
and homed in place to full-pin contact by the manipulator and the A to D converter card rein- 
stalled in the Sealab rack. The data transmission link was then found to be operating satis- 
factorily. 




Fig. 163. Benthic laboratory manipu- 
lator in position to engage top card in 
module 1 1 



While the cause of the trouble in the A to D link was not conclusively determined, there 
is a strong suggestion that a combination of electrical leakage in the connector in the Sealab 
electronics rack, in conjunction with electrical damage to the diode gate card, were the cause 
of trouble. The trouble was presumably corrected by both the replacement of the card and by 
the removal of the plug from the chassis socket, thereby giving it an opportunity to dry out and 
relieve the severity of the electrical leakage. Manipulation was secured at 2:30 p.m. 



Chapter 44 
OCEAN-BOTTOM MINING TECHNOLOGY 



J. Leslie Goodier 
Marine Mineral Technology Center 
Tiburon, California 



AIRLIFT EXPERIMENT 

General Description 

In the airlift method of mining on the ocean floor, a recovery pipe line is suspended from 
a surface craft to the seafloor (Fig. 164), and compressed air is injected into a manifold loca- 
ted on the recovery pipe some distance above the foot or shoe of the pipe (Fig. 165). The air 
pressure just exceeds the water pressure at the point of air entry into the manifold (Fig. 166). 
The water above the point of entry of the air into the pipe becomes an aerated froth. This re- 
duction in density in the upper section of the pipe results in a pressure differential and result- 
ing water- sediment flow into the base of the recovery pipe. This flow has such velocity that 
solids are raised to the surface, where they are discharged into recovery barrels. 



SURFACE CRAFT 



BARGE 




NODULES OR SAND 



INTAKE SHOE 




OCEAN BOTTOM 

Fig. 164 Air lift method of recovering material from 
the ocean bottom 



402 



OCEAN-BOTTOM MINING TECHNOLOGY 



403 




1/4" t, 29-3/40 Di 
24" I. D. 



2"0.D. X 1-3/4" ID. 
3-3/4" LG. 



LIFTING RING 
2-l/2"O.D. 1-3/8 
3 PLACES 




I X I X 1/8 LS 5-3/4 LG. 
6- EQUALLY SPACED 
WELDED 



Fig. 165. Conical shoe used on the bottonn of the 
air lift recovery pipe 



Sealab II Tests 

An airlift with a two- inch recovery pipe was lowered from USNS Gear in 185 ft of water 
near the Sealab II site. Compressed air was supplied from Gear at 140 psi and 50 cfm. Ini- 
tial two-phase (air/water) flow was established at 10 gallons per minute, one minute after com- 
pressed air was supplied to the manifold. Very few solids were observed in the water flowing 
into the recovery barrels, and pumping was discontinued after 15 minutes. Examination of the 
recovery barrels disclosed only a few ounces of very fine sediment, principally mica flakes 
averaging 2 mm in diameter, and light silica particles. 

Observing divers reported that sediments at the location were highly compacted and cap- 
able of supporting considerable weight. Based on this information, it was decided to increase 
the seawater intake velocity by decreasing the effective area of the shoe. The original shoe 
was modified aboard Gear to Bureau engineer's specifications. 

The diving team was then instructed to distribute several pounds of phosphorescent sand 
over a ten- foot- diameter circle around the recovery shoe and observe the lateral movement of 
the sand into the system with an ultraviolet light. The divers reported no perceptible move- 
ment of the sand; however, phosphorescent sand was observed in the recovery barrel. Airlift- 
ing operations were terminated after 10 minutes. 



404 



OCEAN-BOTTOM MINING TECHNOLOGY 



1/2 AM. STD. PIPE 
COUPLING CUT 1/4' 
It a 4" PIPE TO FIT, 




1-1/2" AM. STD. PIPE 
COUPLING CUT IN HALF, 
ONE EACH END 



1/4 AM STD. PIPE 
COUPLING CUT 1/4" 
t a 4" PIPE TO FIT. 



4" AM STD PIPE, 
9" LONG 



1/4 

2.45" 1. 0., ONE 

EACH END 



SCALE: 1/2"= I" 



Fig. 166. Compressedair manifold on air lift re- 
covery pipe 



The increased velocity of flow doubled the amount of solids recovered. Other factors 
which caused some increase in the amount of solids recovery were the less compact nature of 
the phosphorescent sand and disturbance of the bottom by the observing divers. 

It was then decided to increase the intake velocity further by removing the suction shoe. 
This alteration reduced the weight of the assembly so that a diver could maneuver the intake 
across the ocean floor. The observing divers were instructed to distribute phosphorescent 
sand and 3/8- in., 1/8- ounce steel pellets, vary the height of the intake pipe above the ocean 
floor from to 1 ft, and control air-inlet flow with the valve at the air manifold, 28 in. above 
the inlet. 



The duration of the test was nine minutes, during which time two cubic feet of sediment 
was recovered. Water discharge was black, indicating a heavy sediment concentration. The 
steel pellets were picked up and discharged against the recovery-barrel deflector plate with 
considerable force. 



OCEAN-BOTTOM MINING TECHNOLOGY 405 

Conclusions and Recommendations 

1. The ability to observe actual operation of the air lift on the sea floor is very helpful. 

2. The greater the shear strength of the sediment, the higher must be the shoe inlet veloc- 
ity. This points up the need to custom design shoes to suit the physical characteristics of bot- 
tom sediments. 

3. Baffle plates are needed in the recovery tanks. Solids were lost through the recovery- 
barrel overboard discharge even though 20 and 40 mesh screens were positioned in the lines 
between the two recovery tanks. 

4. The "man handling" of one hundred or more feet of hose creates a considerable 
problem. 

5. An oversupply of compressed air does not help sediment recovery. Excess air has an 
adverse effect, in that it causes the recovery hose to thrash and whip. 

6. Manifolds two and three (Fig. 167) were tested, and each functioned relatively well. 
Time limitations did not permit conclusive volumetric flow measurements. 




32-1/16 DIA. HOLES, 
4 TO ROW, 8 ROWS 



64-1/8 DIA HOLES 
8 TO a ROW, 8 ROWS 



32-1/8 DIA. HOLES 
4 TO o ROW, 8 ROWS 



3-1/2" 

-- 

1" 


1 

1; 



' 1-1/4' 


|\ 








\, 




1-3/4" ^ 




<» 




i 


io 




o, 


4-3/16" ff., 








SINTERED 








BRASS, CUT 








TO FIT AND 




o 




BRAZED IN 


lO 




o' 


PLACED AND 








MACHINED 








INSIDE AND 


io 




o' 


OUTSIDE 




o 






p 


o 


ol 




p 


o 


oi 




Io 




Ol 


i_ 


|o 


o 


0| 


3/4" 


1 







NO. I 



NO. 2 



T 




NO. 3 



NO. 4 



SCALE: 1/2"= l" 
Fig. 167. Types of spools used on compressed air manifold 



ROTARY CORER EXPERIMENT 



General Description 

The rotary coring device (Fig. 168) is 14 ft high and weighs 1,000 pounds in air and 830 
pounds in water. It is made up of off-the-shelf components assembled in a frame with tripod 
legs to sit on the ocean floor and drill a six-foot core of sand, gravel, nodular material, or 
rock. The unit is lowered and raised from a surface vessel, from which power is supplied to 
a motor mounted on the device. The motor is controlled by an operating console on the surface 
vessel. A circulating-water pump on the corer assists the core barrel in penetrating the dense 
sands and gravels. The core barrel is lined with plastic sheet to facilitate core removal. 



406 



OCEAN-BOTTOM MENING TECHNOLOGY 




Fig. 168. Rotary coring device 



Sealab II Tests 

Three tests were made at the Sealab 11 site. Due to the slope of the bottom (approximately 
22 degrees) the unit tipped over each time it was placed on the sea floor. On the first test, a 
six-inch core was obtained before tipping occurred. On the third test the corer fell with suf- 
ficient impact to cause a short in the electrical system which resulted in termination of the 
test. 

Conclusions and Recommendations 

1. A portable coring device designed to rest on the seafloor must adjust to the topography 
of the area. 

2. The power cable must be armored to protect it from sudden shocks and abrasion. 



3. Some mechanical method of handling the power cable during raising and lowering is 
required. 



Chapter 45 
UTILIZATION OF PORPOISES IN THE MAN-IN-THE-SEA PROGRAM 

F. G. Wood, Jr. and Sam H. Ridgway 

U. S. Naval Missile Center 

Point Mugu, California 

BACKGROUND 

The purpose of an ONR funded "Project Arion" being undertaken by the Life Sciences De- 
partment of the Naval Missile Center is to determine the means by which porpoises can be 
effectively utilized in scientific experimentation directed toward naval application. 

Sealab II provided an opportunity to test the feasibility of using porpoises in conjunction 
with the Navy's man-in-the-sea program. With the encouragement and active support of Sea- 
lab II officials, plans were made for on-site field trials with a porpoise trained to perform tasks 
appropriate to Sealab n operations. An Atlantic bottlenose porpoise "Tuffy" was an obvious 
candidate for this due to his participation in a diving physiology study directed by Dr. Sam H. 
Ridgway. Tuffy had made dives to depths in excess of 300 ft. He had been trained to wear a 
harness and to home on two different acoustic devices. He was accustomed to working unteth- 
ered in the open sea. 

PLANNED PROGRAM 

After discussions with Sealab II personnel it was decided that Tuffy's primary task would 
be to simulate the rescue of a lost aquanaut. Poor visibility was anticipated at the proposed 
site of Sealab II. A diver has little if any directional hearing capability, and even electronic 
directional listening devices reportedly are of limited usefulness. 

It was planned that Sealab II aquanauts would be tethered at all times while swimming at 
ranges beyond the visual range of the habitat. Future operations will require that they range 
untethered, relying on electronic aids for navigation to return to the habitat. 

Should a failure occur and the diver become disoriented, a strong possibility exists that he 
will be unable to find his way back to his ocean-floor habitat. 

Future Sealab type experiments will be conducted at increasingly deeper depths, where aid 
from the surface by surface support swimmers will be extremely difficult. Availability of a 
trained porpoise to perform certain vital work functions will thus be increased importance as 
deeper depths are reached, provided the depth limitation of the porpoise is not exceeded. 

As planned, for Sealab II Tuffy would be summoned (by a buzzer, one of the acoustic de- 
vices to which he had been trained to respond) from the surface to an aquanaut at Sealab 11. 
That individual would snap a line to one of the rings on the animal's harness, then turn off his 
buzzer (designated the primary signal). The "lost" aquanaut would then summon the porpoise 
by turning on his (secondary) buzzer signal. After unsnapping the line that Tuffy had carried 
to him, he would have a guide back to Sealab 11. 

The "homing" signal to be used by the animal's handler at the surface was the other acous- 
tic device to which the animal had been trained to respond— a small waterproof strobe light (de- 
signed as survival gear), the discharge of which produces a broad-band click. Tuffy had reliably 
come to this signal from distances of over 500 yards in Mugu Lagoon. 



407 



408 



UTILIZATION OF PORPOISES 



Subsidiary tasks to which this training could be adapted included the transfer of tools, mes- 
sage capsules, and other small objects between surface and bottom and between divers. 

PREPARATION 

Training began at Point Mugu on Aug. 2 and proceeded as planned. Tuffy worked out of a 
floating pen anchored in approximately 80 ft of water. 

Since it would have introduced an undesirable complication to require the aquanauts to 
reward the animal with fish, this reinforcement, after the initial training, was eliminated at the 
bottom, and Tuffy was rewarded only after returning to the surface. For the next nine days he 
continued to work well, with the two divers stationed 50 to 180 ft apart. On the tenth day he ac- 
complished one perfect mission, then refused to respond to the divers' signals. He repeated 
this performance on each of the next three days. When reinforcement at the bottom was re- 
sumed, the animal resumed working. Subsequently a system of random reinforcement at the 
bottom was established, and at Sealab n Tuffy carried a small bag of fish down to one of the 
aquanauts on each initial dive. 

The participation of Aquanauts John Reeves and Kenneth Conda in practice sessions at Point 
Mugu greatly facilitated training and helped insure the success of the trials at Sealab II. 

On Sept. 11, 1965, the component parts of a floating pen 17 X 17 X 10 ft deep were trucked 
to La JoUa and assembled on the beach. The pen was towed to the Sealab II site and anchored 
about 200 yards from the SS Berkone. 

On Sept. 13 Tuffy was transported by H-34 helicopter from Point Mugu to the Quivera Basin 
dock at Mission Bay. There he was transferred to the AVR for its scheduled 1230 run to the 
Sealab site. The porpoise behaved normally and accepted food immediately after being dropped 
into his pen. 

On Sept. 14 and 15, Tuffy satisfactorily performed practice dives to depths of 110, 150, and 
170 ft respectively. Divers of the Operations Support Group of the Amphibious Base at Coronado 
ably participated on both days. The Sept. 15 practice session was conducted about 100 feet from 
SeaJab, and Tuff's performance (Appendix A) provided no reason to assume that he was not ready 
for trials with Reeves and Conda the next day. 

However, in the first trials held on Sept. 16 the porpoise would not dive. The sixth trial he 
made a dive, apparently of 4-1/2 minutes duration, coming within sight of Conda, and close 
enough to Reeves to be touched. But he would not hold still for package or line transfer. Pre- 
sumably the heaving lines and cables, the noise of SS Berkone 's generators, the lights of Sealab 
II, and other conditions existing at the site deterred the animal. (Details of performance in 
Appendix B.) 

ACCOMPLISHMENTS 

On Sept. 17, with Reeves and Conda working in a less obstructed area about 100 ft from 
Sealab (but moving closer in the last trials), the porpoise performed flawlessly, transferring 
tools and mail between surface and bottom, and tools and guide line between divers. His seven 
dives ranged in duration from 1 min 8 sec to 1 min 15 sec. 

On Sept. 18 he again made seven successful dives, with Reeves and Conda working just out- 
side Sealab II. Tuffy responded quickly and correctly to every signal. (For details of Sept. 18 
and 18 dives, see Appendix B.) 

On the afternoon of Sept. 18' Tuffy was required to swim from his floating pen to the landing 
craft of the Operations Support Group where he was maneuvered into his stretcher and hoisted 
out of the water (the large crane on the SS Berkone being unsuitable for this operation). He was 
then transferred by small boat to the AVR at the Berkone, and thence returned to Mission Bay 
for the helicopter lift back to Point Mugu. 



UTILIZATION OF PORPOISES 409 

CONCLUSIONS 

A porpoise can be trained to perform useful and even vital tasks in man-in-the-sea pro- 
grams such as Sealab. It can adapt relatively quickly to a strange and in many ways disturbing 
environment, and once trained will perform with a high degree of precision and reliability. 

The potential value of a porpoise (or other deep-diving marine mammal) will increase as 
future Sealabs are located at greater and greater depths. All of the various ways in which 
trained marine mammals can contribute to the Sealab program have not been determined; it 
is anticipated that further investigations will be conducted in future man-in-the-sea tests. 

The wild sea lions that on several occasions reportedly surfaced in the well of Sealab n 
and respired there during the third team's stay demonstrated that these pinnipeds, at least 
could breath the compressed atmosphere and rise to the surface without injury. It remains to 
be determined whether a cetacean can do this, at least without special training. However, a 
capability for making small-package deliveries to and from the interior of a Sealab would vastly 
increase an animal's value, since this would eliminate the necessity for two aquanauts to don 
suits and scuba gear and go outside for any transfer of small equipment or materials between 
surface and Sealab. It would also greatly speed such transfer, a factor of potentially vital im- 
portance in an emergency situation. 

RECOMMENDATIONS 

Porpoise and/or pinniped personnel should become an integral part of the Sealab program. 
Additional work functions should be investigated and tested in follow-on-at-sea tests. 



APPENDIX A 
PRACTICE DIVES NEAR SEALAB H SITE 

14 Sep 65 - Depth 110 feet . 

Morning Session 
Dive No . Time Remarks 

1 I'OO" Line transfer between divers 

2 1'15" Tool delivery & line transfer* 

3 Not recorded Tool delivery & line transfer 

4 1'14" Tool delivery & line transfer 

5 1'17" Tool delivery & line transfer 

6 I'lO" Tool delivery t 

7 45" Tool delivery, surface to first diver only 

Afternoon Session 

Line transfer 

Tool delivery & line transfer 

Tool delivery & line transfer 

Tool delivery 

Tool delivery 

*In most instances this entry refers to tool or message capsule delivery from surface to first 
diver, line transfer from first to second diver, and tool or capsule delivery from second diver 
to surface. 

tin most instances, Tool Delivery refers to delivery from surface to first diver, from first to 
second diver, and from second diver to surface. At each station the tool or capsule was de- 
tached and another attached. 



1 


2'00" 


2 


1'25" 


3 


1'12" 


4 


55" 


5 


I'll" 



410 



UTILIZATION OF PORPOISES 



Dive No. 


Time 


6 


I'OO" 


7 


1'08" 


8 


Not recorded 


15 Sep 65 


- Depth 150 feet (Dives 1-3) 




Depth 170 feet (Dives 4-7) 


1 


I'lO" 


2 


1'05" 


3 


I'lO" 


4 


1'30" 


5 


1'30" 


6 


1'20" 


7 


I'OB" 



Remarks 



Tool delivery 
Tool delivery 
Tool delivery 



Tool delivery 

Tool delivery to first diver only 

Line transfer 

Tool delivery & line transfer 

Tool delivery & line transfer 

Tool delivery & line transfer 

Tool delivery & line transfer 



APPENDIX B 
DIVING TRIALS WITH AQUANAUTS AT SEALAB 



Time 


D^ 


ive No. 


Time 


0935 




1 


I'lO" 






2 


45" 






3 


56" 






4 




1000 




1100 









16 Sep 65 - Depth 205 feet 

First diving trials with aquanauts. Sky overcast, moderate swells. Tuffy was harnessed 
and released from his pen to swim beside the outboard work boat to the NOTS landing craft 
about 100 feet from the SS Berkone. 



Remarks 

Did not go to aquanauts. 

Tool Delivery - did not go. 

Tool Delivery - did not go. 

Responded to aquanaut's signal only by diving a 
few feet below surface. Reeves and Conda re- 
turned to Sealab II, Tuffy was taken back to his 
pen. 

Tuffy brought out again, this time to work from a 
boat tied to the Berkone directly over Sealab n. 

Responded immediately to signal; from surface 
this looked like a good dive, but Tuffy did not 
go to aquanauts. 

Responded to signal. Conda, at PTC, reported 
later that Tuffy came within sight (18-20 feet), 
made vertical ascent, then returned but 
wouldn't come close. Reeves touched animal, 
but porpoise would not hold still for line or 
package attachment. If apparent diving time 
was correct this was a record for Tuffy. 



Reeves and Conda out. 

Tuffy out of his pen. Divers working in more 

open area over 100 ft from Sealab 11 initially; 

in later dives moved closer. 
Responded immediately to signal from bottom, 

and delivered fish to first aquanaut. 
Delivered mail and returned with an empty pouch. 



1'45" 



4'30"(?) 



17 Sept 65 - Depth 205 feet 

0914 
0921 



0930 



0932 



I'll" 
I'll" 



UTILIZATION OF PORPOISES 



411 



Time 


Dive No. 


Time 


0940 




3 


1'9" 


0941:30 
0944 
0947 
0948:30 




4 
5 
6 
7 


1'8" 
1'15" 
1'12" 
I'll" 


18 Sep 65 


- Depth 


205 feet 





Remarks 

Carried mail to first diver, life line from first 

to second diver. 
Tool delivery and line transfer. 
Large mail pouch delivery and line transfer. 
Tool delivery. 
Line transfer, tool return to surface. 



Again the work boat was tied to the NOTS landing barge near the Berkone. Aquanauts 
Reeves and Conda worked just outside Sealab II. Diving trials began at 0930 and were accom- 
plished in rapid succession. 



Dive No. 



Time 



Remarks 



Not recorded 
1'20" 
ri5" 

I'lO" 
1'12" 

I'll" 

1'12" 



Tool delivery. 

Delivered fish, returned tool to surface. 

Coco Cola delivered, mail cylinder re- 
turned to surface. 

Delivered mail cylinder, returned tool. 

Delivered tools and mail cylinder, re- 
turned tools and fish bag. 

Delivered tools, returned other tools to 
surface. 

Delivered tools, returned mail cylinder 
to surface. 

These dives were performed promptly 
and flawlessly; the animal had ap- 
parently become well adapted to work- 
ing in the Sealab II environment. 



chapter 46 
DIETARY PROGRAM 



W. F. Mazzone 
Submarine Medical Center 
New London, Connecticut 



Although it has long been recognized by the female of the species that the way to a man's 
heart is through his stomach, too little importance has been placed on food and food prepara- 
tion as it may affect morale. If man is expected to live and work on the ocean's floor for pro- 
longed periods of time, efforts must be made to improve his well-being and the so-called 
creature comforts. If man is to be subjected to other than ideal conditions, his motivation must 
not be stinted by being underpaid and underfed. 

In order to appreciate fully the dietary, or lack of a dietary, program for Sealab U, it is 
necessary to have a mental picture of (a) the galley, (b) storage spaces, both dry and refriger- 
ated and, (c) contamination containment. 

The galley area contained a small four-element electric range, without a hood; one double 
sink with hot and cold water taps; a two-compartment refrigerator with a seven and one half 
cubic foot chill space and a freezer space of the same capacity. Other than limited shelving 
for condiment storage, normal day store stowage space was not specifically designed. 

Galley equipment consisted of the electric range, a roto-type broiler, Teflon-coated elec- 
tric skillet, electric sauce pan, and a defective four-slice electric toaster. Needless to say, 
utensils and other items were available. 

Protection against contamination of the atmosphere with potential toxicity hazard con- 
taminants is a very major concern. Under conditions of prolonged submergence in a confined 
space, such as an undersea dwelling or submarine, environment and habitability may be con- 
sidered one of the major limiting factors of endurance. Thus, it is and was essential that cer- 
tain cooking processes be eliminated, such as frying, which may produce acroleins and some of 
the partial combustion products such as carbon monoxide. 

In view of the above factors, it is quite evident that sound dietary programs would be ex- 
tremely limited in scope. 

The U.S. Naval Supply Research and Development Facility, Bayonne, New Jersey, provided 
assistance in the preparation of a diet (Table 46) and load list (Table 47) suitable for ten men 
for 15-day periods. In preparation of the menu, it was necessary to keep in imnd those limiting 
factors previously cited, as well as the following considerations: 

1. All foods must be of the easily prepared type 

2. Packaging must be compatible with extreme pressure conditions, at least 110 pounds 
per square inch absolute 

3. The tendency to get away from total group feeding in favor of individual preparation and 
eating. 



412 



DIETARY PROGRAM 



413 



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414 



DIETARY PROGRAM 



Table 47 
PROVISIONS LOAD LIST - SEALAB H 







Individual Packages 






No. 






or Tins 














45-Day Order 


Total 


Rations 






Items 


Source* 


Total 


Total 


(to nearest 


Cube 


per 






10-Day 


4 5- Day 


Case) 


(Cu. Ft.) 


Package 


, 




Require- 


Require- 






or Tin 






ment 


ment 








Beverage Base, Ass't. Powd., Env-80/case 


8960-782-3132 


30 


135 


2 (160 env.) 


2.00 


2 


Grapefruit, Canned #303 case, 24/case 


8915-132-7786 


30 


135 


6 (24 cans) 


4.38 


1 


Asst. Dry Cereal, Individual - 10/pack 


8920-127-7276 


80 


360 


36 (10 packs) 


2.00 


1 


Ham Omelet - 12 boxes/case 


Bordens 


20 


90 


8 (96 pkg) 


2.88 


1 


Cheese Omelet - 12 boxes/case 


Bordens 


20 


90 


8 (96 pkg) 


2.88 


1 


Western Omelet - 12 boxes/case 


Bordens 


20 


90 


8 (96 pkg) 


2.88 


1 


Mushroom Omelet - 12 boxes/case 


Bordens 


10 


45 


4 (48 pkg) 


1.44 


1 


Milk, Starlac, 12-6 pkg/case 


Bordens 


50 


225 


4 (288 pkg) 


0.96 


1 


Cream, Dry, Coffee-Type (4 oz jars) 


8910-845-4338 






4 


0.52 




Nestle' sQuik 


Wholesale Grocer 






1 


0.75 




Figs, 2-1/2 cans, 24/case 


8915-191-4704 


10 


45 


2 (48 packs) 


2.46 


1 


Cream Chip Beef, #5 cans, 12/case 


Sexton 


6 


27 


2 (24 cans) 


2.20 


5 


Coffee, Instant, 24 - 6 oz jars/case 


8955-753-3366 






6 


7.20 




Beef Stew, #10 tins - 6/case 


Sexton 


1 


5 


1 (6 cans) 


1.10 


10 


Beef Stew, 8 oz cans - 24/case 


Chef Boyardee 


30 


135 


6 (144 cans) 


2.04 


1 


Ham Chunks, 6 #10 tins/case 


Sexton 


1 


5 


1 (6 cans) 


1.10 


10 


Chicken Stew, 12 #5 tins/case 


Sexton 


2 


9 


1 (12 cans) 


1.10 


5 


Chicken Chop Suey, 12 #5 tins/case 


Sexton 


2 


9 


1 (12 cans) 


1.10 


5 


Beef Chop Suey, 12 #5 tins/case 


Sexton 


2 


9 


1 (12 cans) 


1.10 


5 


Spaghetti & Meat Balls 24-6 oz/case 


Chef Boyardee 


20 


90 


4 (96 cans) 


1.36 


1 


Spaghetti & Meat Balls, 6 #10 tins/case 


Sexton 


1 


5 


1 (6 cans) 


1.10 


10 


Beans & Franks, 24-8 oz/case 


Chef Boyardee 


20 


90 


4 (96 cans) 


1.36 




Beef Ravioli, 24-8 oz/case 


Chef Boyardee 


10 


45 


2 (48 cans) 


0.68 




Vegetables & Meat Balls, 24-8 oz/case 


Chef Boyardee 


20 


90 


4 (96 cans) 


1.36 




Chicken & Dumplings, 24-8 oz/case 


Chef Boyardee 


10 


45 


2 (48 cans) 


0.68 




Bean & Beef in Barb. Sauce, 24-8 oz/case 


Chef Boyardee 


10 


45 


2 (48 cans) 


0.68 




Spaghetti in Tomato Sauce, 24-8 oz/case 


Chef Boyardee 


10 


45 


2 (48 cans) 


0.68 




Meat Ball Stew, 24-8 oz/case 


Chef Boyardee 


10 


45 


2 (48 cans) 


0.68 




Peas, 24 - #303 cans/case 


8915-127-9285 


35 


158 


7 (168 cans) 


5.11 


2 


Carrots, 24 - #303 cans/case 


8915-634-2437 


15 


68 


3 (72 cans) 


2.19 


2 


Beans, Green, 24 - #303 cans/case 


8915-616-4817 


30 


135 


6 (144 cans) 


4.38 


2 


Potatoes, Sweet, 24 - #2-l/2/case 


8915-127-3892 


15 


68 


3 (72 cans) 


3.69 


2 


Mayonnaise, Potato Salad, 12 #5/case 


Sexton 


4 


18 


2 (24 cans) 


2.20 


2 


Tomatoes, Canned, 24 #303/case 


8915-221-0361 


5 


23 


1 (24 cans) 


1.23 


2 


Potatoes, Whole, Canned, 24 #303/case 


8915-543-7673 


10 


45 


2 (48 cans) 


2.46 


2 


Spinach, 24 #303/case 


8915-285-2546 


10 


45 


2 (48 cans) 


2.46 


2 


Com, 24 #303/case 


8915-257-3949 


5 


23 


1 (24 cans) 


1.23 


2 


Veg. Soup, Cond., 48 #1 Picnic 


8935-125-9381 


15 


68 


2 


2.96 


2 


Tomato Soup, Cond., 48 #1 Picnic 


8935-125-6307 


10 


45 


1 


1.48 


2 


Peaches, 24 #303 Commercial 


Whlse Grocer 


40 


180 


8 (192 cans) 


9.84 


2 


Pineapple, Sliced, 24 #303 Commercial 


Whlse Grocer 


50 


225 


9 (216 cans) 


11.07 


2 


Pears, 24 #303 Commercial 


Whlse Grocer 


40 


180 


8 (192 cans) 


9.84 


2 


Plums, 24 #303 Commercial 


Whlse Grocer 


40 


180 


8 (192 cans) 


9.84 


2 


Fruit Cocktail, 24 #303 Commercial 


Whlse Grocer 


20 


90 


4 (96 cans) 


4.92 


2 


Cranberry Sauce, 24 #303 Commercial 


Whlse Grocer 


10 


45 


1 (48 cans) 


1,23 


2 


Chow Mein Noodles, Commercial, 














Cardboard Pack 








2 


1.00 




Rice, Instant, 12 - #2-l/2/case 


8920-965-4423 






1 


1.00 





*Sources; a. Military if Federal Stock Number is shown. 

b. Sexton & Co. {Metropolitan Los Angeles) 18383 So. Susana Road, Compton, Calif., 
213-636-3211. 

c. Contact reliable wholesale grocer for: 

(1) Borden's Freeze-Dry Omelet and Starlac. 

(2) Nestle 's Quik 

(3) Chef Boyardee (American Home Food). 



Area Code 



DIETARY PROGRAM 



415 



Table 47 
PROVISIONS LOAD LIST - SEALAB H (Continued) 







45-Day Order 


Total 


Miscellaneous 


Source* 


(to nearest 


Cube 






Case) 


(Cu. Ft.) 


Sugar, 1 lb. cartons 


8925-126-3408 


1 case (24 cart) 


0.75 


Salt, Morton "Salters," Small Shaker Pack 




1 dozen 


0.10 


Crackers, Salted, 1-2 lb. cartons 


8920-252-3838 


3 cases 


9.18 


Crackers, Ritz 


Whlse Grocer 


2 cases (24 pkg) 


2.00 


Butter 


Whlse Grocer 






Pepper, 3-4 oz. can 


Whlse Grocer 


6 cans 


0.10 


Mustard, l/2-l lb jart 


Whlse Grocer 


6 jars 


0.10 


Mayonnaise, 1 lb jar 


Whlse Grocer 


6 jars 


0.10 


Catsup, 12 oz. bottlest 


Whlse Grocer 


1 case (12 bot.) 


0.75 


Pickles, 1 qt. jar 


Whlse Grocer 


1 (1 qt. jar) 


1.00 


Worcestershire Sauce, 5-6 oz. bottle 


Whlse Grocer 


1 dz. bottles 


0.25 


Hot Sauce, 2-3 oz. bottle 


Whlse Grocer 


6 dz. bottles 


0.10 


Jams & Jelly (1 lb. jar) 


Whlse Grocer 


1 dz. asst. 1 lb jar 


0.50 


Garlic Salt, 3-4 oz. bottle 


Whlse Grocer 


6 bottles 




Peanut Butter, 1 lb jar 


Whlse Grocer 


1 dz. 1 lb jars 


0.50 


Raisins, 1-1/2 oz pkgs (192/case) 


Whlse Grocer 


1 case 


0.58 


Peanuts, Dry Roast, 1 lb. jars 


Whlse Grocer 


2 cases 


0.50 


Shrimp, Cooked, Freeze-Dried 


Kraft 


1 case 


1.10 


Cottage Cheese, Freeze-Dried 


8910-082-5734 


1 case 


1.10 


Crabmeat, Freeze-Dried 


Kraft 


1 case 


0.33 


Cheese, American, Dehydrated 


8910-823-6880 


1 case 


1.10 


Juice, Tomato, Concentrated 


8915-616-0204 


1 case 


1.17 


Potted Meat Spreads 


Commercial 


1 case 


0.50 


Shortening Compound for Frying, Grilling, Etc. 


8945-125-6338 


2 - 5-1/2 lb cans 


0.33 


Pork Chops, Raw, Freeze-Driedt 


8905-253-7328 


2 cases (24 cans) 


2.00 


Beef Steaks, Raw, Freeze-Driedt 


8905-753-6536 


2 cases (6 cans) 


2.00 



♦Sources: 



Military if Federal Stock Number is shown. 
" • ■ b. Sexton & Co. (Metropolitan Los Angeles), 18383 So. Susana Road, Compton, 
Calif, Area Code 213-636-2311. 
c. Contact reliable wholesale grocer for: 

(1) Borden's Freeze-Dry Omelet and Starlac. 
(2)Nestle's Quik. 

(3) Chef Boyardee (American Home Food). 
tSecure in plastic squeeze bottle, if available. 

JSpecial procurement, if desired - Defense Personnel Support Center, 2800 South 20th St., 
Philadelphia, Pa. 



By and large, the majority of foods provided for use were of the 
Three separate items were included for test and evaluation: 



'heat and eat" variety. 



1. Commercial, freeze-dried omelet mix for breakfast meals and sandwiches 

2. Commercial tinned whole milk preparation, Sterifresh, marketed by Sausner Foods and 
provided gratis by the New York Office of the Small Business Administration. 

3. Plastic prepackaged meals, frozen, provided by Thomas Distributing Company, Newport 
Beach, California. This package could be immersed in boiling water for up to 15 minutes for 
thawing and cooking. 



During the bottom stay for each team, aquanauts were requested to comment upon the de- 
sirability of meals. In the main, meals were considered palatable and generally good, although 
midway through each of the periods, some of the aquanauts complained about the monotony of 
the meals. In subsequent conversations, it developed that variety is in fact the spice of life, 
and that a good thing can be overdone. 



416 DIETARY PROGRAM 

In an effort to overcome some of the minor disenchantments relative to Sealab n being a 
"feeder," it became necessary to supply additional items such as fresh bread, fresh fruits and 
vegetables, pastries, and from time to time, meals prepared by verily compassionate inhabi- 
tants of the La JoUa, California Area. The daily supply of surface supplied goodies was min- 
imal for team three. Since team three was to have the last bottom exposure for the operation, 
it was decided that it would be interesting to evaluate how well a team could subsist from the 
sea. The menu provided a vast assortment of fish, served raw in the style of the Japanese, or 
cooked in such a manner as to minimize atmosphere contamination. 

Body weight was obtained each morning and recorded by the medical officer. Though the 
specific weights are not available at this time, each aquanaut reported that weight remained 
approximately the same, and in two cases decreased as much as three pounds. 

By general observations via closed circuit television monitors, it appeared as though eat- 
ing became more than just a necessity. On an average, though specific calorie accounts were 
not maintained, the aquanauts were of the opinion that they had consumed at least one-fourth 
again as much food each day as normal. These opinions were confirmed by observation. 

The opinions of the aquanauts confirm that a ventilation system should be provided for the 
galley area which, by necessity, must contain equipment for control of atmospheric contaminants 
generated in the process of cooking. It is necessary to review the problems and resolutions as 
applicable to atmospheric control maintained in nuclear-powered submarines. Secondly, it is 
essential that adequate storage space be included in the design modification. An area such as 
the conning tower might well be adapted to dry store stowage, with ballast requirements shifted 
externally. 

Thirdly, and again very important, is the requirement for greater frozen storage without 
a loss of chill space. As the depth increases, it will become more and more difficult to pro- 
vide surface support. Consequently, if any degree of autonomous operation is to be achieved, 
storage of essential items is an absolute must. 



Chapter 47 
AAARK-VI MIXED-GAS BREATHING APPARATUS 

J. C. Bladh and P. A. Wells 

U. S. Navy Mine Defense Laboratory 

Panama City, Florida 

INTRODUCTION 

The initial preparation of gear and the training of Sealab personnel in the use of the Mk-VI 
Scuba was accomplished under the supervision of the Mine Defense Laboratory Diving Officer. 
Experience gained from Sealab I dictated that the following preparations and procurement of 
material must first be accomplished to support the training as well as the Sealab II effort it- 
self: 

1. Procure 20 Mk-VI rigs 

2. Build a Mk-VI locker and gas rack 

3. Procure portable recompression chamber 

4. Procure mixed gas (He0 2 and NO 2) and CO2 absorbent (Baralyme) 

5. Establish a training schedule and lesson plane 

6. Schedule boats as required 

7. Enlarge present diving locker and shower room to accommodate Sealab personnel 

8. Procure transfer pump (PPI) for charging rigs 

9. Procure adequate gas analyzers 

10. Establish and procure a Mk-VI spare-parts inventory. 

PREPARATION 

On Feb. 1, work commenced at the Mine Defense Laboratory, fabricating a Mk-VI locker 
and work area. This included the construction of a gas rack, drying rack, vest stowage, suit- 
able work benches and lockers, as well as a new locker and shower room. This work was 
completed by Apr. 1. This locker was used as a guide for the construction of the Mk-VI locker 
aboard the support vessel. 

On Mar. 28, 20 Mk-VI units arrived at the Mine Defense Laboratory from the Naval Oper- 
ations Support Group Pacific and immediately were given a visual inspection, cylinder test, dip 
test and operational test. In addition to the above, and as an added safety factor, three Hansen 
fittings from each unit were modified to provide a positive lock to the hose fittings. Two of 
these modified Hansen fittings are located at the control block and one at the canister. 

During March, the following gas and equipment were procured to support the training pro- 
gram. 

1. 10,400 cu ft He 

6,160 cu ft 60/40 N2O2 
2,640 cu ft 40/60 N2O2 
3,960 cu ft 32.5/67.5 N2O2 
2,200 cu ft N2 
4,400 cu ft O2 

2. A two-lock portable Dixie recompression chamber was obtained from Explosive Ord- 
nance Disposal Unit TWO, Charleston. In addition to the above, utility boats, YSD's and MSO's 
were programmed and scheduled to support the training program. 

417 



418 MARK VI MIXED-GAS BREATHING APPARATUS 

TRAINING 

Mk-VI training commenced on Apr. 5 for the first class of 18 aquanauts and support divers. 
This was a four -week course broken down as follows: 

1st week - 4 days classroom 

1 day pool indoctrination 

2nd week - 1 day 30 ft Gulf 
4 days 60 ft Gulf 

3rd week - 5 days 100 ft Gulf 

4th week - 1 day 160 ft Gulf 

3 days 180 ft Gulf 

Each man spent 15 days diving and made 20 dives for a total of approximately 7 hours in the 
water with the Mk-VI scuba. 

This first class used only the appropriate N2O2 mix, as authorization to use He02 had not 
yet been received from the Bureau of Medicine and Surgery. On May 1, authorization to use 
He02 was received from the Bureau of Ships, provided that a portable chamber and submarine 
medical officer was present on the scene. On May 3 the second class of 20 Aquanauts and sup- 
port divers commenced their four-week training period. Their schedule was as follows: 

1st and 2nd weeks were the same as for class 1. 

3rd week - 1 day 66 ft HeOz 

4 days 102 ft He02 

4th week - 1 day 145 ft HeOj 
3 days 190 ft He02 

During this second class each man spent 15 days diving and made approximately 20 dives for a 
total of 8 hours and 30 minutes in the water. The additional time in the water for the second 
class can be accounted for by the fact of the extra decompression time required while using 
He02. By comparison, the Mk-VI course conducted at Underwater Swimmers School, Key West, 
provides for only 2-1/2 hours in the water; however, consideration must be given to the fact 
that the Underwater Swimmers School course is geared to teach the relatively inexperienced 
diver. This course completed the initial Mk-VI training. It had been programmed for one ad- 
ditional week of diving for the first class using HeO 2. This did not materialize due to additional 
training requirements coupled with the tight schedule on the West Coast. 

The open-sea dives were conducted in the Gulf off Panama City in 30 to 200 ft of water; 
visibility ranged from 20 to 60 ft; hard packed bottom sand; water temperature approximately 
70 F on the surface and 65 F on the bottom. During the months of April and May not one day 
of training was lost due to inclement weather. The diving class was supported by the UB-102 
(Diving Boat) and YSD for the shallow dives and by Mine Division Eighty-one (MSO's) for the 
deep dives (over 100 ft). 

TRANSPORTATION OF EQUIPMENT 

The 20 Mk-VI rigs were originally packed in cardboard containers. Because of the distinct 
possibility of damage in this type of packing, it was decided to procure fiberboard steamer 
trunks and outfit them with molded ethafoam packing. Twenty-four trunks were outfitted, 22 for 
the Mk-VI rigs, one for test ki